In Diablo 4, Mutterlock Chests appear to resemble silent chests but there are a few differences. You have to mutter a phrase to open them
You may have come across a certain chest with golden locks while grinding through different dungeons in Diablo 4. This chest appears to be like a silent chest but is rarer and shows up when you’re taking on high-difficulty endeavors such as those Nightmare Dungeons. The chest in question is called the Mutterlock Chest.
You may consider yourself lucky if you find one so make sure to keep an eye out for it. While it appears similar to Silent Chests, you can’t open it with Whispering Keys.
To open the Mutterlock chest you will have select the right phrase from the options given to you.
