UFC flyweight contender Casey O'Neill issued a challenge to a fan who claimed women's MMA is inferior.The fan, who hides behind a faceless burner account on Twitter, singled out O'Neill as someone they labeled "low level," while taking a shot at the entire women's MMA scene. The Twitter user, who admitted that they are untrained in combat, suggested that they can fight better than the Scottish-born Australian.See the tweet below:cal davies@CalDaviesss1@kingcaseymma is genuinely such a low level of fighter. Women's mma in general is low level but Casey is something else. I have no fighting experience at all but could still fight better than she does.71@kingcaseymma is genuinely such a low level of fighter. Women's mma in general is low level but Casey is something else. I have no fighting experience at all but could still fight better than she does.Not one to back down from any confrontation, 'King' Casey asked her detractor to put their money where their mouth is. She unhesitantly revealed her whereabouts and extended a challenge:"[Xtreme Couture] in Las Vegas. Tuesday/Thursday is sparring day. 3:30pm, Come spar me, that would be fun!"Check out Casey O'Neill's response below:Casey Oneill@kingcaseymma@CalDaviesss1 @XC_MMA in Las Vegas. Tuesday/Thursday is sparring day. 3:30pm 1152@CalDaviesss1 @XC_MMA in Las Vegas. Tuesday/Thursday is sparring day. 3:30pm 😊Casey Oneill@kingcaseymma@CalDaviesss1 Come spar me, that would be fun !1368@CalDaviesss1 Come spar me, that would be fun !Xtreme Couture head coach Eric Nicksick even gave O'Neill his blessing to spar the fan. His only condition is that the person signs a waiver. Meanwhile, Chris Curtis said he'll be ready to get the cameras rolling.Eric Nicksick@Eric_XCMMA@kingcaseymma @CalDaviesss1 @XC_MMA Just sign the waiver. 🫡2329@kingcaseymma @CalDaviesss1 @XC_MMA Just sign the waiver. 🫡Chris Curtis The Action Man@Actionman513@Eric_XCMMA @kingcaseymma @CalDaviesss1 @XC_MMA I am definitely filming this. Lol I love that he called out a woman though. Super brave973@Eric_XCMMA @kingcaseymma @CalDaviesss1 @XC_MMA I am definitely filming this. Lol I love that he called out a woman though. Super braveNeedless to say, it's never a good idea to call out a professional fighter, especially for people who have no experience in fighting. But, of course, social media is a place where trolls can thrive without having to face actual consequences.With O'Neill's latest experience, it's hard not to think back to the time Paul Felder had a hilarious exchange with a self-aware keyboard warrior.Check out the interaction below: View this post on Instagram Instagram PostUFC flyweight Casey O'Neill's road to recoveryUFC flyweight standout Casey O'Neill was supposed to face Jessica Eye on the main card of UFC 276 in July.Unfortunately, the up-and-comer suffered an ACL tear, which forced her to withdraw from the matchup. On Instagram, O'Neill announced that the injury will require surgery and that she'll be out indefinitely:"I've spent the past 7 days trying to continue on but it's just not possible on a fully torn ACL... I will have surgery, recover and be back better than ever before you know it. I’m so sad that I don’t get to perform for you guys, I’m so sad that I don’t get to fight but I am excited to get healthy and rebuild."Check out the post below: View this post on Instagram Instagram PostRight now, though, the UFC flyweight prospect appears to be hard at work on returning to action. Based on her social media activities, O'Neill mainly spends her time rehabbing her injury and participating in light martial arts training.