A Poison Cursed Seal is destroyed when the turns that indicates on the Curse ends.
A Poison Curse is one of the easiest (easy to use and create a deck) ways to win a game. A Poison Curse deck focuses on Poison Cursing at opponent Seals, and defending the attack from opponent Seal. The easiest way of defending of the Poison Curse deck is just "not attack". Because the opponent Seals get Poison Curse, he or she will do nothing but to attack your Seals before his or her Seal dies from Poison Curse. From this reason, You just wait for the opponent Seal to attack and then spells a Mystic Card to win or stop the battle.
A Poison Curse is often found on [Water], and [Dark]. It is also found on [Insect], and [Evil], but it is found them less than is found on [Water] and [Dark].
An example of a Seal that has a Poison Curse Skill is Mysterious Elephant.