A phrase commonly used in
World of Warcraft to tell players to avoid spells (like poison clouds, rain of
fire, tail sweep and similar) that often deals massive damage to players and thus can cause a wipe.
This phrase apply to all kinds of harmful spells, even if they're not coloured
green or coloured at all.
Encounter example:
The early
boss Grobbulus in the raid-instance Naxxramas in WoW have the ability to put out
green poison clouds under him. If the raidmembers stand in it they
will die because of the damage.
Phrase example:
The raidleader have been explaining the tactics and ends with: "And don't stand in green shit."