Damage Threshold. The mech is capable of withstanding damage better than most creatures. If a single attack deals less than 20 damage, the damage is instead reduced to zero.

Innate Spellcasting. Zectapyro's innate spellcasting ability is Dexterity (spell save DC 16, +8 to hit). It can innately cast the following spells, requiring no components.

• At will: Create Bonfire, Thaumaturgy, Burning Hands (3rd-level).

• 3/day: Fireball (5th Level).

Multiattack. Zectapyro makes either a Bite attack and two Claw attacks, or two Flame Burst attacks. 

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 3 (1d6) fire damage.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Flame Burst. Ranged Weapon Attack: +9 to hit, range 160/600 ft., one target. Hit:  20 (3d6 + 10) fire damage.

Fire Blast (3 Times Per Long Rest). Zectapyro exhales fire in a 35-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 42 (12d6) fire damage on a failed save, or half as much damage on a successful one.