Help with line: "Must have had some kind of self-destruct."

I’m reading the newest Jim Butcher book, Proven Guilty. The main character has just destroyed a monster, and when asked about it he says:

“I didn’t hit it all that hard. Must have had some kind of self-destruct.”

Then he’s disappointed that another character misses the “classic” reference. I can’t place it either, and it’s bugging me. I can almost hear Kirk saying this, or Han Solo. Help?

Han Solo said it when they shot the Imperial probe droid on Hoth.

Oh god, I’m such a geek…

Of course he did. Thanks, Max!