Hey, so let's say you have a legendary creature enter the battlefield with flameshadow conjuring, and you pay the one red to copy it and give it haste. The legend rule then applies, but is there a way to work in collateral damage to kill the main or copy of the legendary creature? Like could one do it in response to the legend rule? Is there some way to make this work?
You can’t respond to state-based actions, so there’s no way to keep the original and sacrifice the token to something like Collateral Damage unless you have a Mirror Gallery.
On the other hand, you can sacrifice the original creature to an effect like Collateral Damage while the Flameshadow Conjuring trigger is on the stack. The token will still be created if you pay R and will survive until the end step as normal.