|[List of appearances]|
Aaron Cash was one of Arkham Asylum's toughest, most respected guards. While on duty, Killer Croc went on a rampage, requiring various guards to contain him. When Cash attempted to pacify him, he was attacked, resulting in the loss of his left hand. This was replaced with his signature hooked hand.
The LEGO Batman Movie
As The Joker began causing havoc throughout Gotham City with the Uber-Villains, Cash was among the staff at Arkham Asylum. While Barbara Gordon dealt with Batman's break-in to send his arch-nemesis to the Phantom Zone, Aaron caught the commissioner's attention, only to show her a video of a puppy and a monkey.
This is a description taken from LEGO.com. Please do not modify it.
You have to be gruff, rough and tough to make it as a security guard at Arkham Asylum, and Aaron Cash is one of the gruffest, roughest and toughest there is. He doesn’t take any nonsense from the asylum’s many super-villain inmates, no matter how big and bad they may be – even after the unfortunate lunchtime incident with Killer Croc that left him with a hook for a hand!
Bat-Fact: Actually thinks the hook makes him look pretty cool.