Venomoth is one of Rusty's pokemon.
Venomoth was summoned by Rusty during a Gym Fight with Blaine, but he was easily burned and killed by Growlithe. In Ghost Tower, Venomoth returns as a ghost to haunt Rusty, declaring that he's the worst trainer ever. As Venomoth and the rest of the Ghost Pokemon tries to kill him, Grandpa Crispen intervened and convinces his dead Pokemon to guide him to become a better trainer. Venomoth and the rest of the ghosts fled when Crispen is captured.
In Bidocalypse, Venomoth was most likely to die again in the altered timeline due to Future Rusty's repeated actions.