Boarsilisk

Charge. If the boarsilisk moves at least 20 ft. straight toward a target and then hits it with a tusk attack on the same turn, the target takes an extra 7 (2d6) slashing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.

Lethargy Gaze. 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 14 Constitution saving throw if the basilisk isn't incapacitated. On a failed save, the creature is considered under the effects of the Slow spell as a wave of lethargy washes over it. It can repeat saving throw at the end of each of its turns. On a success, the effect ends.

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 boarsilisk until the start of its next turn, when it can avert its eyes again.

If it looks at the boarsilisk in the meantime, it must immediately make the save. If the boarsilisk sees its reflection within 30 feet of it in bright light, it mistakes itself for a rival and targets itself with its gaze.

Relentless (Recharges after a Short or Long Rest). If the boarsilisk takes 14 damage or less that would reduce it to 0 hit points, it is reduced to 1 hit point instead.

Tusk. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 4) piercing damage plus 4 (1d6) poison damage.