Clash Royale is one of the best mobile games, popular among players because of its graphics and unique cards. These cards are of various types like troops, spells, and defenses. Users should combine these as 8-card decks to win multiplayer battles.One of the strongest spell cards in Clash Royale is Poison, highly effective while pushing attacking troops.Poison Card in Clash RoyalePoison is an Epic card (Image via Sportskeeda)Once gamers reach Arena 9, they can unlock the Poison Card. It is a spell card that does area damage to both enemy troops and towers. It has a large radius of effects and can deal a lot of damage.The Poison Card's in-game description is as follows:"Covers the area in a deadly toxin, damaging enemy troops and buildings over time. Yet somehow leaves the grass green and healthy. Go figure! Reduced damage to Crown Towers."It's a powerful spell card because it not only destroys enemy troops and towers but also slows down their movement by 15%, allowing friendly forces to assault. Its excellent damage capability can end Musketeers, Ice Wizards, Minions, and various other troops.Clash Royale@ClashRoyaleAs @adrianpiedracr tried to finish off the tower with Poison, @AtchiinWu's Battle Ram secured him the title of LATAM Spring Champion! #CCGS3:53 AM · Jul 3, 2017749105As @adrianpiedracr tried to finish off the tower with Poison, @AtchiinWu's Battle Ram secured him the title of LATAM Spring Champion!🏆 #CCGS https://t.co/tlCjqB1aWuIt is an Epic card that can easily replace the Fireball Card due to its high damage ability and wide radius. Players should follow the below-mentioned steps to unlock the Poison Card:First, reach Arena 9, where they are eligible to unlock the Poison Card.The Poison Card can be unlocked by opening chests, through shop quests, and clan donations.Add the card to the 8-card deck and try obtaining more Poison Cards or Magic Items to upgrade the card.How to use the Poison Card in Clash Royale?Clash Royale@ClashRoyaleWhile @AtchiinWu's Poison and Skeletons tore a tower apart, @colton_wall's PEKKA crossed the entire arena, and finished off the tower with one final swing!With that, @colton_wall has defeated the Latin America Spring Champion! #CCGS2017Finals2:27 AM · Nov 15, 201724714While 🇧🇷@AtchiinWu's Poison and Skeletons tore a tower apart, 🇺🇸@colton_wall's PEKKA crossed the entire arena, and finished off the tower with one final swing!With that, 🇺🇸@colton_wall has defeated the Latin America Spring Champion! #CCGS2017Finals https://t.co/d2YY0ztjNwIt is a highly effective troop in Clash Royale when used with high-damage building target troops like Giants and Hog. It saves such troops from swarms of troops like Minions and Skeleton Army.The ability of the Poison Card to reduce the speed by 15% makes it highly effective against cards like Night Witches and Witches that additionally spawn troops.It can also help troops like Miner and Goblin Barrel clear towers as it protects them from swarms of troops.The Poison Card is no doubt one of the best spell cards in Clash Royale that can easily replace the Fireball Card in the deck. It should be used alongside high damage and hitpoint troops like Giant and Pekka.