Mouth Pool

Strategy
Warning #1: You need strong off-hand items to survive on the tenth wave. Piggy Mc' Cool is already very strong, so you don't need to worry about him. If you have potions, only use them if a bird is almost dead.

Warning #2: Only in wave 4 and after, when the Rage Chili is full, use it for Bomb to deal much damage to all undeads, or Matilda to massively heal. Don't use it in the first 3 waves.

Choose Matilda in Druid, Bomb in Capt'n and Piggy Mc' Cool's Merchant Pig. In wave 1, attack Spirit Caller until he runs away. In wave 2, attack the Ghost and heal with Matilda until the Spirit Caller runs away. In wave 3, attack the Frankenpig until the Spirit Caller runs away. If the Frankenpig attacks, heal with Matilda. In wave 4, attack Spirit Caller until he charges 1 turn, and then weaken the Stinky Zombie and the Poltergeist and use the Rage Chili for Bomb. They won't revive before the Spirit Caller runs away. In wave 5, weaken all undeads until they are almost all knocked out. When the Spirit Caller is almost running away, knock out the undeads one by one. In wave 6, weaken all mummies, dispel the Will-o-Whisp's Ethereal with Bomb and in the next turn use the Rage Chili on Bomb after healing with Matilda. In wave 7, attack every turn the Voodoo Berserkers and, when the Spirit Caller runs away, knock them out. In wave 8, attack the Banshee and in the next turn heal with Matilda and use the Rage Chili on Bomb. In wave 9, attack the Frankenpig and then the Zombie Knight. When the Spirit Caller runs away, knock them out one by one. Keep the Rage Chili for the last wave. In wave 10, attack the Spirit Caller. When he uses Mass Leech, use the Rage Chili for Matilda to cleanse the effect and heal. When he attacks with Om Nom Nom, heal with Matilda. Repeat this over until you win or either lose.