Period monster 

Something you call women when they are really mad to calm them down. Should always be used if you have an upset wife/girlfriend.

My girl was being all mad and attacking me, so I called her a period monster and she settled down and started feeding me grapes.

Period monster by Tyler Peniston June 3, 2020

angry period monster 

A female who is currently undergoing PMS, or her menstrual cycle.

An angry period monster, or APM, often exhibits the following characteristics, including, not but limited to, violent mood swings, irrational behavior, frequent irritating text message sending, being annoying, ruining your day, destroying your concentration before a test, and just being an overall bitch.

Also called angry menstruating monsters, or AMM's (pronounced "AY-DOUBLE M").

A typical text message conversation between a male and an angry period monster:

(9:43 AM) APM: can't wait to see you this fridayy!
(9:45 AM) Guy: yeah, can't wait
(9:46 AM) APM: you know what, fuck you. you're a fucking asshole.

...

(9:48 AM) APM: wtf is your problem asshole??
(9:51 AM) APM: you know what? im just done. bye.
(9:54 AM) APM: are you fucking kidding me? what the fuck is your problem?

angry period monster by big tall giraffe March 4, 2011