Picking up a jar of Bomb Paste upgrades your bombs into 'Sticky Bombs' which glue to whatever they touch. Bomb paste may be sold in a variety of different shops and can also be found randomly within crates or when enough sacrifices are made at an Altar. Additionally, a jar of paste is guaranteed to drop when a Giant Spider is killed (along with a couple of jewels). You do not run out of paste however many bombs you use, and the upgrade is irreversible.