I feel tentacles rising, slithering up, wrapping themselves around my brain, consuming it.
My full mental power comes to my defense.
I hack, but Doubt creeps up again and takes over my head.
—
For Trifextra. The challenge is to write 33 words on a beast in an unusual place. Hope this qualifies.
Sandra's scribbles 
Have you read Grace Black’s take on this exact beast? You both did excellent!
Doubt is one of the worst kinds of beasts.
Very cool!
Doubt.. can be a beast.. well described.
I know this beast well. Somebody slay him already.
A powerful beast indeed and you never know when he might visit.
A great take on the prompt.