Lockjaw

Transmutation
Level: Druid * 2, Hunter * 2, Ranger * 2
Components: V, S, M (sticky tree gum)
Casting Time: 1 Standard Action
Range: touch
Target: creature touched
Duration: 1 round/level
Saving Throw: Fortitude negates (harmless)
Spell Resistance: yes (harmless)
  You give a creature the ability to use one of its natural attacks to firmly attach itself to an opponent. Choose one of the creature's natural attacks (usually a claw or bite attack).
  The creature gains the Grab ability with that natural attack, including the +4 bonus on combat maneuver checks to start or maintain a Grapple. A creature with multiple natural attacks can strike at its Grappled opponent with its other natural attacks, but cannot attack any other creature.