partypooper 

One who breaks up or ruins a party through a variety of means. Possible ways of dispersing or destroying a party include but are not limited to: calling the authorities, stories involving octogenarian sexual intercourse, Jennifer Aniston movies.

Rich: Oh no, Larry! Here comes Harold.

Larry: He's probably going to come over here and talk about his wife. She just died. God, what a partypooper.

Rich: What a selfish bastard! What makes him think we care about that?

partypooper by The Master of Unlocking January 22, 2010

Partypoopers 

A group of friends who goes to parties without participating in the party, which therefore often kills the mood.

- See who just walked in through the door, it's prutskid and friends
- Oh, they're such partypoopers

Partypoopers by Mr. meeeeeeeeeee April 11, 2011

Partypooper 

The opposite of Partygoers in The Backrooms. Very friendly and are humanoid with jackets and a blue mask with a sad face. Resided in The Boredom Room but, after The Fun War, now live in The Promised Land

Man I wish The Partypoopers were still around

Partypooper by ThatAnonymousBloke April 6, 2022

Partypooper 

A partypooper is a entity that lives in level 777(I think)and are small numbered because of the fun war with partygoers

Oh a partypooper

Partypooper by Camthefurry October 4, 2022