It's not the threats that get to Dave. This gang of superheroes is a pretty tough bunch, and he knows for a fact that Karkat is more capable of staying sane despite serious shit (up to and including the influence of a crazy homicidal clown). But those little hints of the Joket knowing more than he should, really knowing and not just guessing, that's unsettling. And that combined with the "pookie bear" garbage...

The stony mask slips for a second, and Dave flushes bright red.

He recovers quickly enough, at least, but maybe not enough to remain as cautious as he should be. Wash is down for the moment, and Dave is a Knight. It's more instinct than anything else that has him flashstepping forward to plant himself betwern Wash and the clown, taking a swing with his sword in hopes of at least pushing the Joker back a bit. The fucking joy buzzer comes as a surprise in the worst way, when the Joker grabs at the blade instead of dodging away and hits him with a nice little electrical charge.

Dave seizes up at the shock, a sensation like a thousand pins jabbing into his hands and forearms, and it's a solid few seconds before he can manage to move his hands enough to drop the sword and stagger backwards, teeth grit through the lingering pain.