Mike mentioned mimics in yesterday’s dev stream, but mentioned that it might be hard to implement them in a way that doesn’t affect the game too much. He threw out the idea of having a dungeon that has mimics. I missed the dev stream so I couldn’t comment in real time, but wanted to point out two thoughts.
First, one of the reasons people enjoy mimics comes from tabletop gaming, where it’s possible for a mimic to be strong enough to kill or seriously wound a weaker character. I suspect that’s why Mike was hesitant about incorporating them into LE - how can you bring them in without affecting balance too much? My response to that would be to make them either a normal, magic, or rare monster. Making them Champion-level might be a bit much, but if you or your build can’t handle a surprise rare mob that’s kind of on you, I think.
The other thing I’d like to say is that while it could be fun to have a whole dungeon where they can show up, it could also be fun to just make one chest in Unclaimed Trove or Vault of the Barnacle King a mimic. I suspect Mike might’ve been thinking of this in terms of making it so there’s some small percentage that any chest could be a mimic, but the other way to handle it would be to make it so that only 1 chest in each echo could be a mimic, and then whether or not you happen to click on that chest is up to chance.
Of course the whole goal in Unclaimed Trove and Vault of the Barnacle King is to open every chest, so you’d definitely find it in those, but in other echoes if there’s only 1 per echo then you might not see them every echo. I know I don’t click on every chest, but I’ll click on a few here or there if they’re close and I’m not feeling swamped at the moment.