There’s no rule that says dead creatures can’t take action. You’ll usually become Unconscious first, but instant death effects including massive damage bypass that. So you can just keep playing.
This was clearer in 3.5, where it actually had an entry for the Dead condition which did not say you couldn’t take actions.
Dogs aren’t a playable race so they can’t have class levels. But there is no rule saying dogs can’t learn languages. And they can be Sidekicks, but that’s more a rule specifically designed to allow them to play. There’s also no rule saying they can’t wield weapons. One-handed and two-handed weapons both require hands to use, but there aren’t actually any weapons listed as one-handed.
I think nonliving creatures may be more specific versions of objects then, since I couldn’t find any reference of creatures not being considered objects (because who would even say that, it should be obvious if you use your brain), but it also means that if a spell or ability only allows you to target or create objects and has no specification in regards to creatures, undead and constructs are valid targets by RAW.
If you look up the definition for an Object, it specifies that it is “a nonliving, distinct thing” — such as a corpse.
However, the definition of Creature does not say it must be living. So, a corpse is both a creature and an object.
There are even creatures that have never been living — such as constructs — and thus are also objects.
There’s no rule that says dead creatures can’t take action. You’ll usually become Unconscious first, but instant death effects including massive damage bypass that. So you can just keep playing.
This was clearer in 3.5, where it actually had an entry for the Dead condition which did not say you couldn’t take actions.
There’s no rule saying a dog can’t play!
Dogs aren’t a playable race so they can’t have class levels. But there is no rule saying dogs can’t learn languages. And they can be Sidekicks, but that’s more a rule specifically designed to allow them to play. There’s also no rule saying they can’t wield weapons. One-handed and two-handed weapons both require hands to use, but there aren’t actually any weapons listed as one-handed.
That’s on the same level as disintegrate making you able to play a sentient pile of dust.
I think nonliving creatures may be more specific versions of objects then, since I couldn’t find any reference of creatures not being considered objects (because who would even say that, it should be obvious if you use your brain), but it also means that if a spell or ability only allows you to target or create objects and has no specification in regards to creatures, undead and constructs are valid targets by RAW.