Calgulum the Subjugator

Whenever you cast a creature spell, if Calgulum is not mounted, you may have that creature spell become an Aura spell with enchant creature. If you do, attach it to Calgulum and it becomes mounted. While mounted, Calgulum gets +X/+Y where X is the mount's power and Y is the mount's toughness. It gains all abilities of the mount. If Calgulum would be dealt lethal
damage while it is mounted, inst