Ruling Cursegar + Gengar Prime

[StealthAngel667]

Quick one here.
If you, say, would be having a Gengar AA active and would use its attack to KO PokeX and skip into Gengar Prime, would you then proceed to put PokeX into the Lost Zone in accordance to Prime's Body?
Because from my experience, you first do everything else that the attack tells you to (or in this case: allows you to, switching is optional), then you check for the KOs. So I'd say from this guideline that the answer is yes, supplying us with yet another broken Gengar.
On a side note, would this work the same for Pokes that bounce to the hand?

 

[DNA]

Yes. If you Shadow Skipped and placed Gengar Prime as your Active Pokemon, Catastrophe would trigger, since all effects of attacks are checked for before applying knockouts.
In regards to Pokemon that bounce back to the hand...I would assume that Active Pokemon are replaced first before checking KO's, due to the ruling about Uxie's Psychic Restore in the Compendium:

Q. If I use Uxie's "Psychic Restore" attack to KO my opponent's Pokemon, then place Uxie back onto the bottom of my deck, who replaces their Active Pokemon first?
A. Uxie is gone before KO's are checked, so the Uxie player replaces first. (Jan 8, 2009 PUI Rules Team)