Slimefun adds 3 "special" Bows, the Icy Bow, the Explosive Bow and the Soulbound Bow. They act like a normal bow as well - you can put enchantments on them - but they also have a special ability.
The Explosive Bow launches the entity it hit up into the air.
The Icy Bow gives any entity it hits slowness and a negative Jump Boost for 2 seconds, preventing them from moving.
The Soulbound Bow is not dropped on death.
See: Soulbound Weapons