Spooky Jack

Spooky Jack is a halloween-themed trinket that summons a pet.

Source
The item can be purchased in East End Police Station (heroes) or The Gotham Tap Room (villains) during The Witching Hour event.

=Spooky Jack= Upon activating the trinket, Spooky Jack is summoned to aid the player in battle. Spooky Jack to aid the player in combat. Spooky Jack stuns enemies that are attacking you

Attacks

 * Ball - does a single attack for 40 damage (on training dummy).
 * Beam - does four consecutive attacks, each for 14 damage (on training dummy).