Plague-Rat 

A person who brings badness or misfortune to people. Some do it on purpose, but this can also be an opinion someone has of themselves due to lack of good self-esteem.

Every guy she broke up with had his mother kidnapped. She must have been a plague-rat.

Plague-Rat by ShutDesFuckUp June 6, 2011

Plague Rat Tail 

An item on EverQuest, introduced from the start, that sold for around one platinum per tail. This is the main way for starting players to make money. There is talk of Sony lowering the value of (or "nerfing) the plague rat tail, but this is only a rumor.

GofG has slain a diseased field rat.
GofG looted a Plague Rat Tail
GofG looted a Rat's Claws

Plague Rat Tail by [e-mail] January 1, 2006

Plaguerat 

A person who wears a mask incorrectly or doesn’t wear one at all during the COVID-19 pandemic of 2020.

Person 1: Did you hear Robby wears his mask with his nose hanging out?
Person 2: Omfg I can’t stand these fucking plaguerats.

Plaguerat by valorflame August 30, 2020