What is a “pet freeze glitch” or whatever it’s called?

I was in a public server the other day trying to get one of those new bunny’s for a frog that I had rotting in my inv and some kid came up to me screaming and ranting about how I was gonna scam everybody and steal their pets using the “ pet freeze glitch “ (I don’t really remember the exact name of it) but I was wondering if that’s a real thing or that kid was just trying to be annoying.