Opponent played Hooded Blightfang. It's a nonland creature with no abilities that would block targeting by Legions to Ashes. Legions to Ashes allows me to exile opponent's target nonland permanent and any tokens with the same name. The opponent also had nothing on the field that would've prevented Legions to Ashes from working or targeting their permanents. Regardless of these facts, I was unable to target Hooded Blightfang with Legions to Ashes.