Accidental Innuendo: Xavier has a knack for this trope. For instance, in one episode, a woman tells Xavier her husband beats her because he loves her. Xavier responds "If that's love, I'm going to make some love to his mouth!"
Alternative Character Interpretation: Is Xavier operating on a level beyond our understanding, or is he just some douche who doesn't have the slightest idea what he's even saying most of the time?
Bizarro Episode: It might seem impossible considering how Mind Screw the show is even at its most normal, but "Damnesia Vu" and its Sequel Episode "Damnesia You" take the weirdness to a whole new level. It's hard to properly describe in words, but both forgo any kind of plot altogether and instead just having Xavier go through various doors into alternate universes, none of which make any sense at all, only to find himself back in the room where he started, with no explanation.
Crosses the Line Twice: In episode four, Xavier doesn't eat a baby. He eats seven, pulls out one of their skeletons, makes a herd of bloodhounds tear an eighth baby to shreds, turns in to a fetus, gets electrocuted, transforms into an egg, hatches, promises to put babies in a stranger's butt and sticks his tongue down her throat. It's even weirder than it sounds.
In the episode before that, a kid's father is blown up, but the explosion is brought to life and becomes one with the kid's father. It's a little creepy. Then the kid stabs the explosion to death with a knife to keep his promise to his mother not to be another Einstein, and it's surprisingly poignant. Then Xavier rips the explosion's heart out and eats it, and it's hilarious.
Squick: Hoo boy. Damn near every episode. One episode involves Xavier repeatedly turning himself inside out.
Ugly Cute: Despite being a creature with a beak, snake hand, six nipples and backward knees in the Deranged Animation sense, Xavier still has a decent following of people who find him rather...appealing. Just look at the fanart.
Uncanny Valley: The intentionally low-quality CGI makes everything seem like a bizarrely unconvincing imitation of reality, be it places, objects or people. Xavier might actually be the most normal-looking thing in the show. Part of the reason for the trippy feel it has (besides, y'know, everything else).