Infernal Soul Factory

Whenever a nontoken creature you control
would die, you may instead have it become an
Equipment artifact and lose all other card types.
If you do, it gains "Equipped creature gets
+X/+X" and "Equip {x}" where X was the
creature's power, and loses all other abilities.
"Apparently you can bind a soul into steel.
Da says it's but a myth. It's called... enchainment?"
—Annal of House Ringstone's 5th Generation Blacksmith, Kira Colstone - Volume XXI