Repsac is a male ghost character who appears exclusively in JumpStart Adventures 4th Grade: Haunted Island.
Repsac has four 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 body is dark blue. Like most depictions of ghosts, he has no legs or feet, and his body ends in a wisp.
Repsac also appears to always be grinning. Even when expressing disappointment (be it sarcastic or legitimate), his lips maintain a smile.
Not much is known about Repsac, but he is known to be a menacing ghost who serves Ms. Grunkle. He 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.
Repsac can be encountered on any of the island paths, and it is also possible to encounter him in the Labyrinth. Repsac can also still be encountered after the player has completed the game's goal of defeating Ms. Grunkle and rescuing the kids, if the player chooses to keep exploring the island afterwards. If the player uses the map, Repsac's appearances are less frequent.
- "[Laughs evilly] Boo! I am the keeper of the island, Ms. Grunkle's loyal servant. You must solve my riddle, or risk your health."
- "Are you ready for another riddle?"
- "You again? I love a good challenge."
- (If a question is answered correctly) "You're right. But I'll stump you...next time."
- (if a question is answered correctly) "Rats. You may have won this time. But I'll get you again."
- (If a question is answered incorrectly) "Hmm...too bad. [Chuckles] That'll cost you some health points!"
- Repsac is "Casper" spelled backwards, which is quite fitting considering that Repsac's personality is the complete opposite of that of Casper the Friendly Ghost.
- Repsac could have possibly led to this version of JumpStart 4th Grade being replaced (by JumpStart Adventures 4th Grade: Sapphire Falls) as too many children were frightened by his sudden appearances.
- The digital manual for JumpStart 4th Grade contains an image of a ghost that appears to be an early design for Repsac that never made it into the final product.
- In the digital manual, Repsac's name is always written with all caps.
- The bugs in the spider web seem to refer to Repsac as "Random threat".
- If Repsac's considered a villain, he ties with Ms. Grunkle & Polly Sparks as the very first villain ever to appear in the JumpStart series.