What is the longest play on record?

With the season over, I wondered what the longest-recorded play in CFB is.

I don't mean long as in yards, I mean long as in time. What is the most time it took for a play to go from the snap of the ball to the whistle, indicating the play has ended?

I can imagine something on the order of a long pocket pass by the offense that gets intercepted, then maybe ran back and tossed back a few times in a desperate attempt to score a defensive touchdown or even fumbled and scooped up by either side.

Surely not more than 30 or 40 seconds, right?