Why is the Basilisk’s CR so low?

Question

A basilisk has a hardy pool of HP and can force players to save-or-die constantly. For a party of low-level adventurers, going purely by CR, one should be a normal-ish challenge, but I don't know how said players could ever deal with the save-or-die mechanic of being turned to stone.

Compared to other CR 3 challenges, or even simply other encounter-xp-pool-appropriate challenges, having a save-or-die mechanic (even one with loopholes if the party knows what they are doing) seems harsh.

I am DM-ing for a party of 5 level 3 adventurers. Compared to other challenges I've thrown at them according to the DMG one basilisk should be in the easy-medium range, but I can't stop imagining at least one of the PCs getting more or less permanently removed from the game based on two bad die rolls.

So why is the basilisk's CR so low when it could potentially insta-kill PCs (and the 'cure' is something that they wouldn't have easy access to at the level where a basilisk is a challenge), and how does it compare to other similar-level challenges?

Answer 1

Petrifying Gaze isn't save-or-die for the party

To apply the Gaze, the basilisk have to see the character, and the character must be within 30 feet. The Gaze affects target at the start of the target's turn (more about it down below).

If a creature starts its turn within 30 feet of the basilisk and the two of them can see each other, the basilisk can force the creature to make a DC 12 Constitution saving throw if the basilisk isn't incapacitated.

The affected character isn't petrified. To become petrified they must fail the saving throw twice:

On a failed save, the creature magically begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified

The more important part, a character can become completely immune to the Gaze at the start of their turn:

A creature that isn't surprised can avert its eyes to avoid the saving throw at the start of its turn. If it does so, it can't see the basilisk until the start of its next turn

They still can attack the basilisk though, even in melee. The only drawback would be disadvantage on attack rolls against the target they cannot see.

Since the Gaze works on the target's turn, the basilisk cannot just approach and apply the Gaze. It can only approach and wait for the target's turn. On its turn, the target just averts its eyes, move back, adjusting the distance, and then look at the basilisk normally and makes a range attack.

Other Basilisk's stats are close to the Nothic's ones, which is CR 2

A Nothic has 15 AC and ~45 hit points. Its melee attacks are slightly weaker. Its Rotting Gaze forces a character to make a similar CON saving throw with DC 12 or take 10 necrotic damage. Without the Gaze, I'd say the Basilisk have a CR 2 monster's stats.