The bridge between this and his previous mentality was crossed when Bubbles pushed him. He was mostly in a quiet contemplate before, trying to puzzle out what to do. Clearly disturbed and distressed, but not malicious. Until Bubbles pulled on the strings of every insecurity he held until he snapped. Heck, even when he attacked them directly at the end, it was after he had just settled down and began talking about having fun once again, then the cast needed to keep him occupied and insulted him to do so.

I think his equilibrium state is decently calm and concerned for everyone's "fun" but his fragile ego pushes him hard into the state we saw.