In the episode, "Death and Stuff," when the dead guy is in the chair, Dan is on the ground looking at the fridge because its broken, and he's reading the fridge manual he just got off the table. While Dan is bent over, the guy's hand slaps him on the butt so Dan gets up, and moves his chair. This causes the chair to fall, and the dead man falls with it. If you notice, as soon as his hand has contact with the ground, it moves so that the man falls without hurting himself. If he were truly dead, then this wouldn't happen.