My phone glitched while using Snapchat.

So, around a minute ago I was on my phone. On my phone I was using Snapchat, but then all of a sudden it was like someone was controlling my phone, it started typing “Lmmmmmm” and started ringing and taking photos the screen had lines everywhere, I pressed the power button and it was okay, then the battery went from 27% to 17%. I am currently resetting it from Google find my device.