Peek-a-Boos are Rabbid enemies in Mario + Rabbids Kingdom Battle. They are enemies capable of teleporting to certain parts of the battlefield, thus evading normal "line of sight" techniques. Peek-a-Boos' long range allows them to snipe characters from afar while also outflanking them. They can also lure characters towards them and out of cover.
The only times they are moving without teleporting is when they are either hit with a weapon that has a chance of either Burn, Push, or Bounce or when Rabbid Mario's Magnet Dance is active.