Kings Rock (item)

Held in battle : Holder’s damaging moves have a 10% chance to make their target flinch. This chance applies independently to each hit of a multi-hit move.

This item’s chance is rolled independently of any other move effects;

E.g., a move with a 30% chance to flinch normally will have a 37% total chance to flinch when used with this item, because 3% of the time, both effects activate.

Held by poliwhirl or slowbro : Holder evolves into politoed or slowking, respectively, when traded.