Being bitten by a Shellder shocked this Pokémon into standing on two legs. If the Shellder lets go, it seems Slowbro will turn back into a Slowpoke.
Hidden Ability
The Pokémon is oblivious, keeping it from being infatuated, falling for taunts, or being affected by Intimidate.
The Pokémon sticks to its own tempo, preventing it from becoming confused or being affected by Intimidate.
The Pokémon has a little of its HP restored when withdrawn from battle.