A sentient piece of faeces that grows legs and climbs out of the toilet to eventually track down its owner and consume their body. Flongus are usually found to form after the owner has eaten their weight in food in one day (and survived), the flongus is actually just disgusted by the amount of food you eat and believes the world would be better without you. Once the flongus has completed its mission it will peacefully return to the toilet it came from and flush itself
Child: ahhh... 45kg of food in one day, beat that dad

Dad: son, whatever you do do not go to the toilet today or face the wrath of the flongus!
by Kitchen🅱️ench June 5, 2018
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A term used to describe someone who has a rather loud assclap while dancing or shaking hips.
You will experience Flongus if you have not practiced your twerking skills.
Jimmy: " Hey Jennifwa, wanna dance to Daft Punk?"
Jennifwa:" Sure Jimmy! My body is ready!"
*Jennifwa starts dancing to Around the World*
* loud clap sounds out of nowhere*
Jimmy: " Umm, Jennifwa, did you just Flongus?"
Jennifwa: "....sorry"
by Balls Are Handy January 7, 2013
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A big fucking spider, that you tried to kill, but it ran away.
Brin: bro why you hidin
Freshpeter: FLONGUS
Brin: fuck
by Avocado worshipper October 4, 2019
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