Misty's special lure
From Bulbapedia, the community-driven Pokémon encyclopedia.
Misty's special lure is a fishing lure created by Misty herself to help with her fishing for Water-type Pokémon. It is a small model of herself in chibi style. She believes it to be the best in her collection of lures.
She has used it herself several times.
She gave it to Ash as a gift in The Unbeatable Lightness of Seeing. He used it to fish for Buizel in DP034, and when Dawn asked to use it, he refused, leading to a short squabble between the two. Later in the episode, Buizel stole their rods, including Ash's with the lure attached; when they recovered them, Ash was glad to see the lure was still okay.