Off-guard

I gave an answer that was way out in left field when the teacher caught me off-guard and called on me.

Tom's question caught Mary completely off-guard.

They were caught off-guard.

She caught me off-guard.

He caught me off-guard.

You caught me off-guard.

Tom was caught off-guard.

Tom caught me off-guard.

Tom was caught completely off-guard.

Tom got caught completely off-guard.