Basilisk
Medium Monstrosity, unaligned
700 XP
Special Abilities
Petrifying Gaze
If a creature starts its turn within 30 ft. 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. 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 until freed by the greater restoration spell or other magic.
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, when it can avert its eyes again. If it looks at the basilisk in the meantime, it must immediately make the save.
If the basilisk sees its reflection within 30 ft. of it in bright light, it mistakes itself for a rival and targets itself with its gaze.
Actions
Bite
Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) piercing damage plus 7 (2d6) poison damage.
Quick Reference
Running This Encounter
The basilisk should begin combat at medium range, using its deadly gaze attack to lock down threats before closing in. Establish clear line-of-sight mechanics and remind players they can avert their eyes as a reaction, imposing disadvantage on attack rolls. Use terrain to create cover opportunities for the party to break gaze contact. Have the basilisk use its bite as a backup attack when opponents close the distance.
Combat Tactics
The basilisk prioritizes using its petrifying gaze against the most dangerous party member each round, forcing action economy decisions. It circles to maintain line-of-sight while avoiding clustering enemies, and retreats to advantageous terrain when bloodied.
Environment & Setting
Underground caverns, ruins, or dungeons with natural pillars and rock formations that provide cover and visual obstruction. Narrow corridors limit the party's mobility advantage and increase the likelihood of gaze attacks landing.