Theros's underworld isn't quite a revolving-door afterlife, but there are some ways to escape that the particularly clever deceased can use. For example, I brought a rubber toy full of peanut butter for the Cerberus. Who's a good doggy? Yes you are! It was all worth it because I got these really cool European dice from down there. I think I'm supposed to give them to some orphans.
Now that I'm back, I've got a fairly short rules update, most of which applies to Theros. One big batch applies to the original Theros, not Theros Beyond Death, but that still counts, right?
As usual, you'll be able to find the Comprehensive Rules here on our website and Oracle text updated in Gatherer—at this time, one or both of those might not be updated just yet, so I'm describing a general truth here. Keep in mind that this article was written before the rules changes were finalized in editing, so there may be minor deviations from what I describe below.