Miss Mantis is the school librarian and she likes it quite. You can forget about computers when you enter her library. Miss Mantis prefers card catalogs, micro-phish and the dewy decimal system. Don't you dare put a book back in the wrong place or forget to pay your library fine. Rumor has it she'll eat your brain.
Derrick is the balloon you got at the theme park or carnival that kept trying his best to get away. If he did escape your clutches, because you were distracted by cotton candy, he would laugh his evil helium balloon cackle all the way into the stratosphere.
If Derrick were not able to get away because your mom tied him to your wrist, he would aggravate your dad by bobbing up and down in the rearview mirror all the way home. His favorite prank was silently floating into your room at night when your eyes had adjusted to the dark just enough to see something moving. Gripped by sheer terror, you would pass out till morning. The next day Derrick was lying on the floor lifeless.
Evil balloons have a short life span.