After receiving orders from Ghostmaster, Arborak was the first entity that attempted to take the Ghostbusters alive. It appeared in the Firehouse and smashed Janine Melnitz' desk. It caught Peter Venkman and Ray Stantz in webbing, but was captured after Slimer slimed it and Winston Zeddemore threw a Ghost Trap into its mouth and activated the trap. In the aftermath, the Ghostbusters questioned why a ghost would try to ambush them at headquarters.
Arborak wanted to kill the Ghostbusters until the Ghostmaster reminded it that he wanted them captured alive.