[Clipper]

It's pretty clearly singular. So you choose one of the monsters and it will ignore you, but the other will keep attacking.

If you are meaning to ignore both the combatant and the helper, then yes, that's fine too, or at least I think so, as long as the helper doesn't count when looking at which monsters ignore you. Note that the turn player is the only one that could actually play this card as well, I think.