Multiattack

The hydra bites once with each of its heads.

Bite

Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit: 10 (1d10 + 5) piercing damage.

Fire Breath (Recharge 5-6)

If the pyrohydra has at least 4 heads it breathes fire in all directions. Each creature within 30 feet makes a DC 18 Dexterity saving throw taking 59 (17d6) fire damage on a failure or half damage on a success.