Arachnid Automaton

Lightning Absorption. Whenever the giant mechanical spider is subjected to lightning damage, it takes no damage and instead charges its electric discharge ability.

Bulb Burst. If the giant mechanical spider’s abdomen bulb is attacked and the spider drops to 0 hit points the bulb explodes with a burst of lightning energy. All creatures in a 30-foot radius of the exploding spider must make a DC 15 Dexterity saving throw, with disadvantage if they are wearing metal armor. Each creature takes 27 (6d8) lightning damage on a failed save, or half as much on a successful one.

Electric Discharge (Recharge 4-6). Every time the giant mechanical spider uses a shocking bite or web shock, it loses its electrical charge in its bulb. Until it recharges, bites have no lightning damage and creatures restrained by webs cannot be shocked.

Multiattack. The giant mechanical spider can make two stabbing attacks with its leg blades.

Leg Blades. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.

Shocking Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) piercing damage, and if it has a charge in its bulb it may choose to also do 13 (3d8) lightning damage as well, using up the charge.

Wire Web. Ranged Weapon Attack: +5 to hit, range 30/60 ft., one creature, only has 3 canisters of webbing loaded to fire. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 14 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 12; HP 7; immunity to bludgeoning, poison, and psychic damage).

Web Shock. A single wire connects the web to the spider’s mouth and as long as this is not severed, the spider may use a bonus action to deliver 13 (3d8) lightning damage to a creature restrained by the web, using up its electrical charge. It may stay connected to the most recent web it has fired.