High-Five Ghost (also known as "High-Five," "HFG," and even (by Muscle Man) "Fives") is a ghost who works alongside Mordecai and Rigby as a groundskeeper at The Park.
Fives appears as a typical white, transparent "bedsheet ghost" figure, except for the hand growing from the top of his head. This hand can shift positions, or even morph into more than one limb, as HFG requires.
High-Five Ghost can currently be found in Champion's Paradise.
HFG gives the player a High Five Ghost Set if the player has defeated the enemies in Peach Creek Wilds and gotten fourth place in the racing there. Fives also helps the player to fly to different locations. In one mission, High Five Ghost asks the player to spy on Slade and Muscle Man.
- Even in official sources, the spelling of his name wavers among "High-Five," "High Five," and "Hi Five."
- In Season One of Regular Show, HFG was voiced by Jeff Bennett; in all other seasons, he has been voiced by Regular Show creator and voice of Mordecai, J.G. Quintel.
- Fives's brother, Low Five Ghost, has the power to change living people into ghosts. It is possible for those who have been so transformed to be changed back, possibly by scaring another person. It is not certain whether Fives himself has either this power or the power of re-transformation back into a living person.