An Astromon made of impenetrable stone. Magma flows within its body, and will sometimes leak from cracks in its stone when the Pebbol is feeling unwell.
Evolution brings with it a greater amount of magma in a Bouldir's body, making it look at times as if it's on fire. Bouldirs have a habit of panting when they breathe, expelling heat from their bodies as they do. For this reason, they are often the Astromon of choice when living in cold areas.
Its giant from and intense heat have earned Granitus the nickname "walking lava." Although usually slow when moving, in battle they can spin rapidly and use the momentum to deliver devastating attacks. Legends speak of a giant Granitus that lives in the Magma Crags.