McGee

Melvin is a character of the day who appeared in The March of the Exeggutor Squad. He is a struggling magician who always had bad luck.

When Misty ran into him at a carnival in Kanto, his assistant had just quit on him. Feeling bad for him, Misty became his new assistant, but it didn't improve his magic show.

When Ash was questioning Melvin about what good his Exeggcute was, they used Hypnosis on him, putting him under Melvin's control. He had Ash weaken a group of Exeggutor, which Melvin proceeded to capture. He planned to use them to hypnotize everybody at the carnival into attending his show.

However, after his own Exeggcute evolved into Exeggutor, it hypnotized the other Exeggutor into stampeding throughout the carnival, destroying everything in sight. Melvin didn't know what to do, but with the help of Misty and Ash's Charmander, he was able to create his own fire to snap the Exeggutor out of their hypnosis and return everything back to normal.

(Source: Bulbapedia)