off the chain
adj.— «Off the chain: An inmate term, not necessarily derisive, for officers acting slightly wacky or making wisecracks at inmates. As in, “Looks like the sergeant’s off the chain today.”» —“What the lingo means” by Adam C. Smith, Jo Becker St. Petersburg Times (Florida) Dec. 30, 1999. (source: Double-Tongued Dictionary)
Further reading
What if, instead of being an inanimate object, a dictionary were alive? That’s the idea behind a lavishly illustrated new children’s book called The Dictionary Story (Bookshop|Amazon) by Oliver Jeffers and Sam Winston. This is part of a...
Chad in Hilliard, Florida, wonders about the expression old as Methuselah, meaning “extremely advanced in years.” The phrase references Methuselah, a figure in Jewish, Islamic, and Christian tradition said to be 969 years old when he...