l2tank
A shout to a tank who's so bad, they're like a punchline. It stands for learn to tank. Also used in other places, like l2heal or l2grammar.
L2tank! You took one hit and died! What’s next, crybaby mode?
L2heal! You healed the boss and made me sad.
L2grammar! You spelled 'tank' as 'tunk'!