Repsac

Repsac, also referred to as Random Threat by the bugs in the spider web, is a menacing ghost who serves Ms. Grunkle in JumpStart Adventures 4th Grade: Haunted Island.

Appearance
Repsac has three long fingers on each hand with pointed fingernails. His eyes appear to be entirely white with no pupils. He has a large nose and crooked teeth. His skin appears to be blue, but that could be because it's always nighttime on the island. Like most depictions of ghosts, he has no legs or feet.

JumpStart Adventures 4th Grade: Haunted Island (1996)
Repsac occasionally springs upon the user to ask multiple choice questions that will deplete the user's health if answered incorrectly. Most of his questions seem to involve science and grammar, as well as sentence structure. This is presumably due to the fact that the game does not have activities which specifically address these topics.

Quotes

 * "I am the keeper of the island, Ms. Grunkle's loyal servant. You must solve my riddle, or risk your health."
 * "You again? I love a good challenge."

Trivia

 * Repsac is "Casper" spelled backwards, which is quite fitting considering that Repsac's personality is the complete opposite of Casper's.