You must find your way through Killer Croc’s lair to collect all of the plant spores in Batman: Arkham Asylum.
Unlike the Killer Croc boss fight in Origins, his encounter in Batman: Arkham Asylum is pretty underwhelming, to say the least.
Do not get your hopes up after your first meeting because despite how Killer Croc appears in the game, you will only be trying to run away from him while searching for a story-related item in the sewers.
This is the one and only encounter with Killer Croc in the game. There will be no opportunity to land your punches on him. Killer Croc’s lair location in Batman: Arkham Asylum
Given his huge size, strength, and insanely sharp teeth and claws, Killer Croc was placed in a special cell underneath Arkham Asylum, inside the sewer system. After Batman’s chat with Poison Ivy regarding the anti-venom for the Titan formula, she sends him down to the sewers.
You can start by heading towards the crashed elevator in Intensive Treatment. Search for the control panel using Detective Vision to clear the path down for yourself; head on down and deal with the thugs before entering the gateway to the sewers.
On your way down through Intensive Treatment, you will face the Scarecrow, after which he gets chased into the sewers threatening to dump his fear toxin in the water.