Harnessing Spine

Symbiosis (If you cast this card, it's an artifact equipment spell that attaches to target creature when it enters the battlefield. If you equip it, it becomes an artifact equipment. It becomes a creature again if it's not attached to a creature.)
Harnessing Spine or equipped creature gains
+3/+1 and "{b}{g}: Regenerate this creature".
Equip {b}{g} ({b}{g}: Attach to target creature you control. Equip only as a sorcery.)