ICE TO MEET YOU
Shatter 3 Frozen Enemies with a single slam attack
Borderlands The Pre-Sequel ICE TO MEET YOU – Achievement / Trophy Guide
A good place to get this achievement/trophy is OUTLANDS CANYON. You can find a lot of CRYO VINES that freeze enemies but not kill them instantly. The video shows an area which has lots of tork enemies that will follow you around.
The difficult part is to get 3 of them close enough to the cryo vine. Most enemies can be frozen multiple times so this makes it a little easier. If you just manage to freeze 2 enemies for example, you can wait until they start moving and try again. When you have 3 enemies frozen, simply stomp them with your slam attack.