Abrupt Decay

Oracle Text

Abrupt Decay can't be countered by spells or abilities.

Destroy target nonland permanent with converted mana cost 3 or less.

Card Rulings

3/14/2017 The converted mana cost of a creature token is 0, unless that token is a copy of another creature, in which case it copies that creature’s mana cost.
3/14/2017 If a permanent has in its mana cost, X is considered to be 0.