Muppetant

When one who holds muppet-like qualities turns snarky, vicious or militant.

This quick, violent reaction from an otherwise peaceful (and somewhat slightly dull being) tends to be an automated response to those who feign intelligence or sexual prowess.

Alternatively, it may just simply be a muppet cutting sick. And so muppets should.

You're being rather muppetant don't you think?

Is something wrong with Tom? Nah, he's just having the muppetants.