Alright, Psycho Plasm... They wanna use status attacks? We'll do the same.
First, slow that mutt down to a crawl with Thunder Wave, and then floor him with a Thunder attack. End the round by waiting for him to come at you to Crunch you, and then, when he opens his mouth, give him a taste of YOUR Toxic. And I mean taste...
If he's too Paralyzed to Crunch you, then just launch the Toxic at him like normal.
Move: Thunder Wave, Thunder, Toxic