Mimic near normal Chest
When I tried to open it, it started to attack me! So be careful using Inventory Editors, not to add yourself a killer chest.
Know what you've done?
Congrats, you just tested a theory for us all. As long as it isn't changed, you've proven that there is a simple and effective way to check for mimics, and thereby gain the best possible loot. Just carry a chest with you for testing purposes (and you might as well have the "Death Chest" mod on while doing...that is probably a good idea too).