Collateral Damage 

Getting multiple kills with a single bullet since the bullet passed through one enemy and hit the other(s). Originated from the military term for unintended consequences of military operations.

In some shooters, this is either completely impossible or only possible under certain circumstances. For example, you can only get collateral kills in Splatoon 2 with charger-class weapons.
In some shooters, certain weapons might still qualify for collateral damage despite having splash damage. For example, the Spartan Laser in Halo qualifies for collateral damage because the laser can pierce through players.

Alternatives: Pierce Kills, Penetration Kills, Chain Kills, One-Bullet Combos, X Birds with One Stone/Bullet
Shortened: Collateral

(from a YouTube video)
Oh, baby a triple! Oh yeah! And that was my triple collateral in Free-For-All.

(custom example)
Would you believe that some player with a charger got insane collateral damage on us?! One shot with the E-Liter, and my team was wiped. We lost that Turf War HARD.

Collateral Damage by The_Epicness9000 May 21, 2020

Collateral blockage 

When you piss off a user on social media enough that every one in the thread that agrees with you is blocked.

Everyone that 'liked' my reply became collateral blockage.

Collateral blockage by Mr. Grime February 21, 2020

Collateral position 

When a 3 man and 1 woman are in a room, one man puts his dick into the mans ass, and that man puts his dick in his other man's ass, then he puts his dick into the women's pussy

The collateral position is on of the most fun positions a group can have.

Collateral position by why yu luk April 8, 2021

collateral relative 

Sibling, pibling, nibling, grandpibling, grandnibling, great-grandpibling, great-grandnibling, great-great-grandpibling, great-great-grandnibling, great-great-great-grandpibling, great-great-great-grandnibling, cousin, first-cousin-once-removed, first-cousin-twice-removed, first-cousin-thrice-removed, first-cousin-four-times-removed, second-cousin, second-cousin-once-removed, second-cousin-twice-removed, second-cousin-thrice-removed, third-cousin, third-cousin-once-removed, third-cousin-twice-removed, fourth-cousin, fourth-cousin-once-removed, fifth-cousin, half-sibling, half-pibling, half-nibling, half-grandpibling, half-grandnibling, half-great-grandpibling, half-great-grandnibling, half-great-great-grandpibling, half-great-great-grandnibling, half-great-great-great-grandpibling, half-great-great-great-grandnibling, half-cousin, half-first-cousin-once-removed, half-first-cousin-twice-removed, half-first-cousin-thrice-removed, half-first-cousin-four-times-removed, double-cousin, double-first-cousin-once-removed, double-first-cousin-twice-removed, double-first-cousin-thrice-removed, double-first-cousin-four-times-removed and etc.

Collateral relative.

collateral relative by MONJZWY June 14, 2023

Triple Collateral 

Normally used in a Call Of Duty game when a sniper kill three enemies with one bullet, nearly the ultimate ecstasy for a "quickscoper".

No way, was that a f*cking triple collateral in the drop zone?

Triple Collateral by BeDiverse February 21, 2015

quad collateral 

when a player in an fps kills four players all at once with one bullet or explosive

"Dude! I just jot a quad collateral with a G- Launcher!"

quad collateral by MidknightXMBJr August 7, 2016

Gossip Collateral 

When two friends both know so many of each others' secrets that they both know neither one of them will tell, or the other one will tell in revenge. For example: Friend A knows X about friend B, and friend B knows Y about friend A. Therefore, if friend A reveals X, friend B may reveal Y, and vice versa. Thus, the security of their respective secrets is mutually guaranteed. Generally, the secrets in question are of equal or near-equal magnitude. For instance, cheating on a partner might be equivalent to a well-hidden drug habit or closet bulimia, whereas a crush would be a lower magnitude.

Becca told Rachel about her secret crush, and didn't have to worry about her telling, because she had Rachel's secret crush as gossip collateral.

Gossip Collateral by Amarantha September 1, 2010