Is an untargetable creature Seen?
Some time ago I used a Berserk effect restricted in the following way: the target received a custom Specifics value and all creatures on the map except the caster of the effect were cloaked by Protection From Creature Type quoting that Specifics value. The berserker could only target, and therefore attack, the caster. Now I'm curious whether those you cannot target are also not Seen or Detected. If so, hiding all but the right creature from the creature you want to manipulate could be a much quicker way of setting targets than going through Nearest, SecondNearest and so on, which may not be practical at all in a large crowd.