She is a deflated Mrs. Puff with a red and blue get-up and a yellow and green helmet.
The Huff is a ruthless, cold-hearted, callous, calculating narcissist and an overall mentally unstable woman who seems to only care about is killing SpongeBob herself. She has an immense loathing and a lethal grudge against SpongeBob because of her deflation, something that SpongeBob was directly responsible for. In fact, she even put SpongeBob in a Demolition Derby, hoping that SpongeBob would die. When SpongeBob wins the derby due to reckless driving, her hatred for SpongeBob boils over the brink that ultimately led to her trying to kill him. Her hatred for and obsession for SpongeBob is so great that she will try to kill him on sight. She is extremely confident to the point of borderline arrogance and appears to be impossible to give up her goals. As such, she has no qualms about endangering the lives of multiple civilians just to increase her chance of killing SpongeBob. However, she regains her sanity once she becomes Mrs. Puff again.