Diggers who keep a close eye on their maps may easily spot potential Juunid areas by the square hallway formation of the ruins. There are several of these reaverbots to be found in the Nino Island Ruins, but they also appear in some of the lesser ruins as well.

Juunid will swim or float gently along in a "shrunken" form (as shown in the lower left screenshot) until approached. When an enemy is near the Juunid will "puff up", turning itself into a very large reaverbot covered with lethal spikes. It will begin to spin as it goes through its corridors, during which time it will deflect all attacks.

Juunid can be attacked before it puffs up or after it comes to a stop. If left alone it will shrink back to its original state.