Foolishly choosing his Butterfree of all options to try and weaken it, Ash was easily rebuffed by the seed Pokémon, to the surprise and shock of everyone—most notably, Pikachu.

I don't have the official numbers on this, but I'd be very surprised if any Pokemon has been turned into a plush more times than Pikachu. I'd also hazard to guess Eevee is close behind ...