Grusper
The term "Grusper" stems from the act of "grusping". A Grusper can be defined as a person that believes that the act in which they are performing is humorous, when in reality it is actually retarded; this is known as "grusping". However, a Grusper can in turn result in an entertaining and amusing outcome given the appropriate situation.
Niko: "I'm so excited to go glooping at Gloopfest!" Jesse: "What the fuck is Gloopfest? That just sounds like some made up shit you came up with. Bro stop being such a Grusper."