Creatures with the Ephemeral keyword should die following combat when locked in as an attacker/defender.

If you have a creature with ephemeral and it gets stunned, or (I believe) has its attack reduced to 0, it's attack fizzles and it returns to bench and doesn't die until end of turn.

It causes an unsatisfactory reaction when you give a unit ephemeral only for it to only die as your turn expires - there's literally no way to kill it off unless the enemy uses a direct damage spell on it or you have Glimpse.

This seems unintended and/or niche, seeing as how you'd need to be running some Ionia/Pilt+Zaun deck to run into the situation where you're facing an ephemeral unit and you can either stun it or burn it and you choose to stun it in an attempt to limit their chance to use Black Spear or Creeping Sensation. That can't be why this interaction is the way it is, right? The only other potential chance for this to 'pay off' is when you have ephemeral units and they don't participate in a fight and you have some source of Rally and you end up wanting to use the ephemeral units in the second round of combat.

Still, just make it so that ephemeral units just de-pop after they're involved in combat, even if they get knocked out due to some effect.

I dunno about anybody else, but I expected my ephemeral dude to go splat after he attempted an attack and was stunned.