Hello everyone!

I'm happy to have found you; I'm pretty new to gardening so it's great to have other people to ask questions to! Here's my question: what would nearly obliterate a previously happy mint plant overnight?

It's a youngish plant itself, but no baby by any means. It's about a foot and a half wide and about that tall. Yesterday it was happy, healthy, thriving, with tons of leaves everywhere. Today I walked out to discover it's been eaten down nearly to a skeleton. A few leaves here and there remain, but even many of the stalks have been gnawed brown. I did find a rather large, dead praying mantis right next to the pot the mint is in, but I didn't think they ate plants so much, I thought they ate pests.

Any ideas on what could have caused this mystery? And how to prevent it in the future?

Thank you all very much!