10 times WWE opened the Forbidden Door

The WWE Universe was rocked this week when the "Forbidden Door" was pried open once again, with stars Chris Jericho, Bryan Danielson and Paul Wight sending messages of congratulations to John Cena during his 20th anniversary celebrations.

The proverbial Forbidden Door opens when a wrestler from one promotion appears on a rival company's show. The term was coined by NJPW's Hiroshi Tanahashi in regards to challenging for the AEW World Championship in 2019.

While sporadic ventures through the Forbidden Door have occurred over the last few decades, such cross-promotional events have become slightly more commonplace in recent times. In fact, AEW and NJPW just recently joined forces to promote an entire pay-per-view based around the concept.

However, in a world where many wrestling promotions are willing to work with one another, WWE has noticeably kept a firm distance. Rarely acknowledging the existence of other promotions, let alone working with outside talent, Vince McMahon and co. seem more comfortable going it alone.

That being said, there have been a number of times where they have reached out and worked with wrestlers from different promotions. In this list, we'll look at 10 occasions where WWE opened the Forbidden Door.

#10. WWE and ECW work together

While Vince McMahon isn't known for his willingness to open the Forbidden Door, WWE is among the earliest organizations to do so on a large scale. Over two decades before AEW and NJPW went head-to-head, the then-WWF opened its doors to Paul Heyman's Extreme Championship Wrestling.

As the Monday Night Wars raged in 1996, WWE was looking for a way to get an edge against its fierce rival WCW. At the same time, ECW was trying to put itself on the map as an alternative to the two mainstream promotions. Both Vince McMahon and Paul Heyman saw an opportunity to work with one another.

After the 1995 King of The Ring was held on ECW's home turf in Philadelphia, McMahon saw potential in the rising promotion. Starting in 1996, ECW stars began making cameos on RAW and on pay-per-view, with a full angle between the two promotions soon following.

Paul Heyman jumped at the chance to feature his company's best wrestlers on a platform like Monday Night RAW and enjoyed the exposure that WWE Superstars would bring to ECW by appearing on his show.

While many feel that the only reason the two companies worked together was because Vince McMahon did not see ECW as a competitor, it was an unprecedented partnership. It's safe to say that McMahon learned a little something from the edgier ECW as his company shifted into the more adult-oriented Attitude Era less than a year later.

#9. WWE and AAA work together

WWE certainly branched out in 1997. Aside from its partnership with ECW, the company also enjoyed a relationship with Mexico's premier Lucha Libre promotion, AAA.

During this time, WCW had demonstrated the success of their Cruiserweight division by signing luchadores such as Rey Mysterio, Eddie Guerrero and Juventud Guerrera, among others. Vince McMahon and company felt that a partnership with a top Mexican promotion could counter this.

At the time, few in the WWF could work in such a style and there was a need to feature outside talent in order to compete with WCW's increasingly popular Cruiserweights. Thus, they embarked on a highly-publicized partnership with the Mexican promotion.

It was a huge deal in Mexico where a large press conference was held to commemorate the partnership. It was announced that the luchadores would make their debuts at the 1997 Royal Rumble. At the pay-per-view, the AAA stars had a match of their own while three luchadores appeared in the Rumble itself.

Aside from the up-and-coming talent, Lucha Libre legend Mill Mascaras also competed in the Royal Rumble and infamously eliminated himself from the match after seemingly forgetting the rules.

Unfortunately, this partnership was not well received by the mainstream audience. Fans did not recognize or connect with the luchadores who were often confined to wrestling among themselves. WWF tried to promote them further with its Super Astros program the following year, but this failed to appeal to audiences outside the Mexican demographic.

Unlike how WCW could integrate its Cruiserweights with the rest of the show, WWE felt the need to keep the AAA Superstars separate from its own wrestlers on TV. Perhaps if they mingled a bit more on-screen, this partnership would have been more memorable.

#8. A WWE Superstar wrestles a WCW star on an ECW show

The only time America's top three companies would collaborate during the Monday Night Wars was when Tazz defeated Mike Awesome for the ECW Championship in 2000. Mike Awesome, who was signed to WCW, was still ECW champion while Tazz, the man who was set to dethrone him, was a WWE Superstar.

Awesome had reigned as ECW champion without re-signing his contract with the company. After a series of pay disputes with Paul Heyman, Awesome decided to sign with WCW before dropping the championship in the extreme promotion. He essentially brought ECW's top title to WCW.

However, WCW feared a potential lawsuit could arise from having the ECW title appearing on WCW TV. They reached an agreement where Awesome would drop the championship to another wrestler. What they did not expect was that the wrestler Awesome would be dropping the belt to was signed to the then-WWF.

Having worked with the rival company in the past, Paul Heyman contacted Vince McMahon about allowing Tazz to return to ECW to win the title from Awesome. McMahon agreed, and for the only time in history, a WWF star wrestled a WCW star on an ECW show.

Tazz held the title for just over a week before dropping it to Tommy Dreamer. Despite that, he would memorably appear on an episode of Smackdown with the ECW title in a loss to Triple H.

#7. Mick Foley appears as Vince McMahon's mouthpiece in Ring of Honor

In 2005, Ring of Honor was still seen as a somewhat smaller scale promotion, but was beginning to find its feet. ROH featured many great talents that turned heads in Vince McMahon's company. One such talent was CM Punk, who soon headed over to the land of the giants.

Meanwhile, Mick Foley began appearing on ROH despite being primarily affiliated with Vince McMahon's company. Although a part-time wrestler, Foley was a somewhat regular fixture on WWE TV from 2004-2005. In between those appearances, he would appear on ROH in a non-wrestling role.

He would feud with Ricky Steamboat and Samoa Joe and worked as both a heel and a babyface. However, his affiliation with WWE was never brought up until an angle with CM Punk in 2005.

Punk was the reigning ROH champion at the time and drew the ire of the fans by declaring that he would leave ROH with its main title and bring it to Vince McMahon's company. Foley then appeared and acted as a spokesman for the company.

Seemingly speaking on behalf of Vince McMahon, he urged the Straight Edge Superstar to defend his title one last time before departing ROH. It added a degree of realism to the already compelling storyline.

Vince McMahon likely allowed Foley to appear on ROH at the time as The Hardcore Legend was no longer a full-time performer with his company. Although Foley did not act as McMahon's spokesperson in real-life, he did admit that he appeared in ROH in search of talent that he could help sign to WWE.

#6. Ric Flair is Inducted into the WWE Hall of Fame as part of the Four Horsemen while signed to TNA

Ric Flair is the first ever two-time inductee into the WWE Hall of Fame. While most remember this fact, fewer people can recall that the 16-time World Champion was signed with TNA at the time of his second induction.

Flair left Vince McMahon's company in 2009 and went to TNA to resume his in-ring career. In the years following his TNA run, Flair admitted that he was enticed by the money he was offered to begin wrestling again following his retirement at WrestleMania 24.

In 2012, Flair was a regular fixture on TNA but had not wrestled since September 2011 following an injury. That same year, Flair's iconic stable, The Four Horsemen, were announced as the latest inductees into WWE's Hall of Fame, and it was confirmed that Flair would join his old comrades in accepting the honor.

As was the tradition, The Nature Boy appeared at the Hall of Fame Ceremony and the next night at WrestleMania 28. To date, Flair is the only star to have ever appeared at WrestleMania while signed to TNA. A month later, Flair left TNA and by the end of the year, he had returned to Vince McMahon's company once again.

#5. WWE allows Intercontinental Champion Christian to appear on TNA

When TNA allowed Ric Flair to appear on WWE TV in 2012, a deal was reached between the two promotions. In exchange for the Nature Boy, WWE agreed to send one of its superstars to appear on TNA programming. The superstar was Christian.

The deal was definitely in TNA's favor as they essentially traded a semi-active legend for one of WWE's top champions. Going by his old name Christian Cage for one night only, Captain Charisma appeared at Slammiversary 2012 to announce the number one moment in TNA history.

Christian was no stranger to TNA as he was active in the promotion from 2005-2008. Following his first departure from WWE, the host of the Peep Show entered the Impact Zone and demonstrated himself to be a capable main event level talent. It was obvious that Vince McMahon and company took notice of this as he occupied a higher place on the card following his return.

After being contacted by the company and told to appear on TNA, Christian initially thought that he was the victim of an elaborate prank. McMahon and company rarely acknowledged other promotions at the time and it was unheard of for them to send one of their champions to appear on a rival show.

Upon finding out that he was truly meant to appear for TNA, the former world champion said that he was honored to be considered for the role. He was happy to return for one night to his old workplace and was glad to have played a part in securing Flair's appearance for the Hall of Fame.

#4. Impact wrestler Rob Van Dam appears on RAW Reunion

You can't have a special episode of Monday Night RAW without Mr. Monday Night. Rob Van Dam himself realized that and decided to appear on RAW Reunion despite being signed to Impact.

Unlike Ric Flair and Christian, whose appearances had to be formalized through a deal, RVD expressed his personal desire to appear on RAW. Fortunately, Impact granted his wish and WWE approved the idea as well.

While many names were advertised for RAW Reunion, RVD's appearance was kept a complete secret and the WWE Universe was genuinely surprised when his theme song hit. Alongside legends Kurt Angle, Sgt Slaughter and The Hurricane, RVD prevented Sami Zayn from running away from Rey Mysterio.

The master of the Five-Star Frogsplash would later thank both WWE and Impact on social media for making this appearance possible. In a way, it was fitting to have someone who appeared during ECW's invasion of RAW in 1997 repeat that same feat 12 years later.

#3. Impact Women's Champion Mickie James appears at the 2022 Royal Rumble

Before the 2022 Royal Rumble, few expected Mickie James to ever return to WWE. Following an acrimonious departure the year prior and her subsequent signing with Impact, it seemed unlikely that the former WWE Women's champion would ever return to Vince McMahon's company.

James not only returned but came back in a big way. Despite being the reigning Impact Women's Champion, Mickie James' entry into the 2022 Women's Royal Rumble match was announced beforehand.

The only thing more surprising than this announcement was the promotion's acknowledgement that she was the champion of another organization.

Unlike other returning Superstars, James did not assume her old gimmick or use her WWE theme. Instead, she proudly walked down the ramp with her current song and wore the Impact Women's Championship on her waist for all to see.

It was good to see WWE successfully mend fences with a longtime veteran who dedicated many years to them. At the same time, it was very memorable for a company like WWE to so openly acknowledge the existence of other thriving promotions.

#2. AEW star Chris Jericho appears on Steve Austin's podcast for the WWE Network

Chris Jericho was one of the first big names to jump from WWE to AEW. Although not permanently signed to Vince McMahon's company at the time, Y2J seemed poised to finish his career there. However, after going through a resurgence in popularity following his stint in NJPW, Jericho chose to sign with Tony Khan's new promotion.

As Jericho's involvement with AEW grew deeper, it seemed that his connection with WWE was growing all the more distant. By the time he became the inaugural AEW World Champion, the company had taken steps to distance itself from Jericho as well. They had removed him from their opening graphic and refused to mention the Codebreaker when it was used by other Superstars.

However, in April 2021, Le Champion would shockingly appear on WWE TV once more. In the days prior, a video was posted promoting an upcoming episode of Steve Austin's Broken Skull Sessions. Fans were quick to point out the familiar countdown tone that Jericho had made famous in the past.

True enough, Jericho was confirmed as Austin's guest. The two legends spoke fondly about their illustrous careers and Jericho spoke candidly about his decision to join AEW. It was also revealed that Vince McMahon personally approved the appearance. It goes to show that while business relationships can break down, friendships can still remain in the industry.

It is also interesting to note that Jericho's NJPW run also took place while he was still affiliated with WWE. The company confirmed that Y2J had permission to work his match with Kenny Omega at Wrestle Kingdom 12. Leave it to the Ayatollah of Rock n Rolla to constantly reinvent himself and pry open the Forbidden Door on his own.

#1. WWE Superstar AJ Styles appears on Impact

AJ Styles is undoubtedly one of the greatest professional wrestlers in the world. Succeeding in every promotion he has been a part of, The Phenomenal One's impressive resume put him on the fast track for success in Vince McMahon's company.

However, it was in IMPACT (then TNA) where Styles got his first big break in wrestling. A star of TNA's X-Division, he put on legendary performances which catapaulted him to the main event scene and got the eyes of the wrestling world on him.

At Slammiversary 2022, the company was celebrating its 20th anniversary and brought back many of its past stars to say a few words to commemorate the occasion. Among those stars was AJ Styles, who delivered a heartfelt video message.

Paying tribute to his time in TNA's X-Division, Styles mentioned how he did not have to possess a huge physique in order to change wrestling for the better. He thanked the IMPACT fans and acknowledged how the company helped him build his career.

Most notably, Styles also thanked WWE in his speech. He mentioned how his current employer understood the importance of such a moment and gave its blessing for The Phenomenal One to appear on the show.

It goes to show that WWE has grown to acknowledge the importance of other companies in the overall careers of its stars.