On the bottom half of the card it says “target all enemies moved through”. What does this refer to? A future attack in the current round? If not this, than what?
It targets all enemies on hexes you moved through in that action. It places Immobilize them immediately, which lasts until the end of their next turn. That will either be: their upcoming turn in the current round, if they have not acted yet in the current round OR their upcoming turn in the next round, if they have acted in the current round.