Trainers » Devolution Spray | Abilities » Eternal Zone
If I have Eternatus VMAX with "Eternal Zone" Ability in play and I use Devolution Spray Z to devolve one of my benched Darkness type Pokemon to a non-Darkness type Pokemon with enough damage already on the devolved Pokemon to knock it out, is it KO'd before having to reduce my Bench down to 5 Pokemon, or if I discard it to reduce my bench is it not KO'd?
You would discard your Bench down to 5 first, then check for a KO. That means you could discard the newly devolved Pokemon to avoid a KO, even if Eternatus VMAX is the one being devolved!
Source: TPCi Rules Team (2020-08-13)
Attacks » Devolution Punch | Trainers » Devolution Spray | Gameplay » Evolving/Devolving
Can you use Devolution Spray or Golurk's "Devolution Punch" attack against a Mega Pokemon, and if so what happens to the Mega Pokemon?
Mega Pokemon are evolved Pokemon, so the Mega Pokemon card is removed, but the underlying Pokemon and all other cards attached stay in play (unless the Pokemon is KO'd, of course).
Source: XY FAQ (2014-02-06), TPCi Rules Team (2014-02-06)
Trainers » Devolution Spray
Can I use two Devolution Sprays on the same Pokemon in the same turn, to devolve from a Stage 2 to Stage 1 and then to Basic?
Yes, you can.
Source: Dragons Exalted FAQ (2012-08-23), TPCi Rules Team (2012-08-23)