Unbonded Symbiote

Bond (Whenever a non-symbiote creature enters the
battlefield under your control, you may have this
creature bond with it. If you do, put this card under
the non-Symbiote creature. This card becomes an
Enchantment Aura and loses all other typings.)

When this creature becomes bonded, the creature it
bonded to gets +3/-1 and becomes a Symbiote in
addition to its other types for as long as it remains
bonded.