@skidkid: There are two points, neither of which is really focused on in the English translation I saw. 1) May has a well-known fear of Tentacruel due to a childhood incident. 2) The opponent has a Malamar, which I would guess is how he hypnotizes her in the first place. Both of those Pokemon have tentacles, so I'd imagine May would easily be bested just by that fact alone. Combined with Malamar's hypnosis, however, she really has no chance.