The Mummy Sarcophagus spawns Mummies that act as guardians of treasures. However, the Prime Evils's influence has infused these protectors with a hunger for human flesh. It is of the utmost importance to destroy these Sarcophagi at once, as many mummies are capable of appearing in a few seconds. Unfortunately, the destruction of the Mummy Sarcophague is a very lengthy process due to its immense durability. Life and Mana cannot be stolen from them and they do not drop any items upon their destruction.
On Hell difficulty, Mummy Sarcophagi are immune to Cold.
A good way to counter Sarcophagi is by standing directly in front of the door (as close to the sarcophagus as possible): this will block the exit and prevent additional mummies from spawning.