The Basilisk is the second-in-command of Impel Down's Level 2: Beast Hell, under the Sphinx. It is a snake born from a chicken as a result of a rare mutation.[1]
The Basilisk is well known and feared among the prisoners. All that is known is that it is weaker than the Sphinx.
History
Summit War Saga
Impel Down Arc
When Monkey D. Luffy and Buggy infiltrated Level 2, the Basilisk attacked them, only to be defeated by Luffy's Gear 3 mode.[1] It did not appear again when the prisoners ran through Level 2 during their breakout.
The Basilisk featured in Impel Down is more similar to a creature known as a cockatrice than a basilisk; both creatures are commonly mixed up and the description of Impel Down's Basilisk matches a cockatrice—not a basilisk.