A house that gained sentience or an "ordinary" being that was transformed into a house? Anyhow, in one of those 2e continuations of a classic 1e adventure (I'm deliberately omitting further details in hopes of avoiding spoilers), there's an isolated tower - curiously shaped like a rook - way out in the boonies; the tower itself is a Mimic! Anyone who has sought refuge within is in for the shock of their lives once they start poking around.