Half-Assed Patterns has a pattern for a Brainmonster hat.

She writes:

Brainmonster is, quite clearly, a brain-eating monster masquerading as a hat. It's based on a hat that I saw on a LiveJournal knitting community, so I take no credit for the (awesome!) idea of a monster hat. There was no pattern offered for the hat I saw, so I improvised my own pattern and now I'm sharing it, because the world needs more head-eating monsters.

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