Enchanted boomerangs can continue flying after hitting a monster, with an enchantment/7 chance. (Add 2 to the effective enchantment if the boomerang is blessed; subtract 2 for each successive monster it hits.) If the boomerang is cursed, enchantment doesn’t matter - it will always fall on the first hit.

The reason behind this is twofold: because it makes boomerangs a more attractive weapon, and for the slapstick comedy value.