Mrs. Puff

Mrs. "Poppy" Puff is a supporting character in SpongeBob SquarePants.

She is SpongeBob's boating school teacher, and with each episode, she grows more and more hateful (and afraid) towards him, even developing somewhat of a phobia. This is most likely due to years of having put up with SpongeBob's failures and the trouble he has caused. However, considering the fact that she has yet to outright tell SpongeBob that she dislikes/hates him, or that he is a terrible driver who will never get his Driver's License, her suffering is arguably partially her fault (though it is still largely SpongeBob's).

Villain Side
Her two most notable antagonistic actions were seen in the episodes No Free Rides and Demolition Doofus. Coincidentally, both involved her tricking SpongeBob into believing her schemes were extra credit.

No Free Rides
""I've got to end this thing before it begins"."

- Mrs. Puff realizing her mistake about passing Spongebob.

Ms. Puff passes SpongeBob from her class just to be rid of him for good. Afterward, she feared that SpongeBob would destroy the town because of her mistake. Later she snuck into SpongeBob's boatmobile and drove off with it, unaware that her student was sleeping in it. The two get into a fight and SpongeBob eventually discovers who the thief was. The boat crashes into a police car and Ms. Puff ends up in jail.

In that episode, it was also revealed she had formerly moved from another town and changed her name. It could be due to criminal history, or otherwise another unfortunate mishap related to her.

Demolition Doofus
""Why are you still ALIVE!?""

- Mrs. Puff's infamous quote from the episode.

After one of SpongeBob's failed attempts at driving, her inflation sac is ruptured and she was told she could no longer inflate, resulting in her hatred of SpongeBob to skyrocket. While at the hospital, she sees injured demolition derby drivers and enters SpongeBob in the annual demolition derby, hoping he would die in desperation to get SpongeBob out of her life. However, much to her displeasure, he survives thanks to his reckless driving, and becomes a star. She then snaps and crosses the Moral Event Horizon by driving a large monster truck and attempting to murder SpongeBob herself. She then regains her puffing ability, however, by crashing into her boating school.

This episode is what many fans of the show consider to be her darkest role. This is what cemented her status as a villainess, as she wanted SpongeBob out of her life so desperately, that she was willing to murder him in order for that to come into fruition.

Trivia

 * Ever since the beginning of the series, Mrs. Puff has had her own criminal record, which explains her being arrested a few times. Such as ditching jury duty or littering, but mostly for Spongebob's wreckless driving and being blamed for it, because it was implied by an officer that driving teachers in Bikini Bottom are held responsible for that sort of thing.