You can only use each effect of "Rescue-ACE Preventer" once per turn
If you need to win but want to stay in mono-white, Lena, Selfless Champion can take Boromir's place and give you infinite creature tokens to win with
Three versions of the legendary creature have been revealed: regular, foil etched, and Memory Corridor borderless with alternate art
This page also lists all of the sets in reverse chronological order, to easily find the one you want
So that means triggering your Hedron Crab also triggers this homarid mercenary, as would targeting them with something like Glimpse the Unthinkable
Players that hate the mechanic consider specialize as very random and impossible to anticipate whats coming next, because people wont have the effort to memorize all the outcomes. Players also criticize the client for handling all the different versions in a confusing way