Basilisks returned in Dark Souls 2, though with some notable changes. For one, their lack of melee capabilities was replaced with multiple attacks, including claw swipes, tail slashes and leaping headbutts. Secondly, they lost their Curse ability, as the changes to the status effect removed the instant death of the previous version. Instead, they gained the ability to petrify their victims, similar to some depictions of the traditional Basilisk.
There is also a much larger and more powerful Giant Basilisk, trapped in a cage in Aldia's Keep in Dark Souls 2.
Basilisks are lizard-like in appearance, with some features common to toads. They have grey scales, with small spines going down their back and extending to the end of their tail. Their legs end in two forward-facing claws and a third on the rear, with a fin-like extension growing from each of their forelegs. The most notable feature is a pair of large, bulbous growths, which are believed by some to be eyes. In actual fact, the actual use of these growths is unknown; their real eyes are the two small glowing orbs above their fanged mouth. On the underside of their neck is a sac, which grows larger before they attack, similar to a toad's own method of intimidating other creatures.
Curse Breath Edit
Basilisks encountered in the first game can inflict the Curse status effect on victims. This kills the victim instantly, and applies a single Curse Stack. Each stack halves the players health, with two stacks dropping them to 1/4, three down to 1/8, etc.
Basilisks encountered in Dark Souls 2 lose their Curse Breath ability in favour of petrification. This allows them to instantly kill their victim, but doesn't have any effect on the player's health.