A fanfic tag that warns you to take the other tags seriously. For example, if one tag says 'non-con', expect non-con.
Don't think, 'ah, it'
s probably just dub-con.' If the tags say 'organ harvesting', expect literal organ harvesting.
Don't take it as a joke or exaggeration. You were warned.
Very commonly misunderstood as a general warning of bad things to come, because it's so often used beside more serious tags, when really it's a specific warning not to take the other tags lightly.
(Originally comes from the TV show Arrested Development, referencing a scene in which the character
Michael Bluth finds a
bag in the fridge that says DEAD DOVE, DO NOT EAT. He opens the
bag anyway, before wincing, and saying, 'well, I
don't know what I expected..')