Melvin is a character of the day from The March of the Exeggutor Squad. He's a magician with a chronic bad luck streak that's basically his defining trait.
Misty met him at a carnival in Kanto right after his assistant bailed on him. She felt sorry enough to step in as his replacement, though his act remained pretty much a disaster either way.
Things took a darker turn when Melvin used his Exeggcute to hypnotize Ash and put him under his control. He forced Ash to weaken a group of wild Exeggutor so he could catch them, planning to use their hypnotic powers to brainwash the carnival crowds into actually showing up to his performances—basically the opposite of a legitimate magic trick.
The plan backfired spectacularly when his own Exeggcute evolved into Exeggutor and ended up hypnotizing the other Exeggutor instead, sending them on a destructive rampage through the carnival. Melvin was completely lost, but Misty and Ash's Charmander helped him create enough fire to break the hypnosis and stop the chaos. So his luck was bad right up to the moment it wasn't.
Content compiled by AnimeList.moe from publicly available sources.
