Evil Pig Bags are magical bags used to locate and capture the Evil Pigs and ultimately revert their curses. When Tomba gets a Evil Pig Bag, he can find the hidden Evil Pig Gate of the same color and encounter the Evil Pig (i.e. the Flame Pig Bag for the Evil Flame Pig).
In order to defeat the Evil Pig, Tomba must toss the Evil Pig into the Evil Pig Bag, which is floating around the area during the battle. In the second game, Tomba must toss the Evil Pig into the Evil Pig Bag three times instead of just one. (Last Evil Pig requires five throws instead of three)