Acronym meaning 'Hyrdated and Dehydrated' describing a skin colour nobody can decide on. Hyrdated and dehydrated are references to urine colours (hydrated being clear/dehyrdated being yellow) when they mix to form a pale yellow. A mixture of white/black/yellow in someone's skin colour.
Jack: What the fuck colour is Tim?
Matt: I have no idea he's like everything mixed into some fucked up colour.
Joey: Yeah he's HAD.