Diesel Drider CR: 7 (2,900xp)
Large mutilated-monstrosity, unaligned
Armor Class: 19 (natural armor)
Hit Points: 136 13d10+65
Speed:
30 ft
, climb: 30 ft
Skills: Perception +5, Stealth +9
Damage Vulnerabilities: Lightning
Senses: darkvision 120 ft., passive Perception 15
Languages: Elvish, Undercommon, Underdraconic, Common
Challenge Rating: 7 (2,900xp)
Uses WIS
Spell mod: +5
Spell Save DC: 13
At will Minor Illusion, dancing lights
1/day each darkness, faerie fire
Morbid Construction. The drider has advantage on saving throws against being charmed or intimidated, and magic can't put the drider to sleep.
Spider Climb. The drider can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Web Walker. The drider ignores movement restrictions caused by webbing.
Drops: Drill Blade
Actions
Multiattack. The drider makes three attacks.
Drill Blade, Light.
Melee Weapon Attack: +9 to hit, reach 5 ft, one target. Hit: 13 2d8+4 piercing damage.
Arm gun, light.
Ranged Weapon Attack: +7 to hit, range 60/180 ft, one target. Hit: 15 2d6+8 piercing damage.
Web (Recharge 5–6). Ranged Weapon Attack: +7 to hit, range 30/60 ft., one target. Hit: The target is restrained by webbing.
As an action, the restrained target can make a DC 12 Strength check, bursting the webbing on a success.
The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).