Thunder Orb

Medium construct, unaligned

STR	DEX	CON	INT	WIS	CHA
10 (+0)	14 (+2)	20 (+5)	3 (-4)	13 (+1)	10 (+0)

Armor Class 12
Hit Points 95 (10d8 + 50)
Speed 0 ft., fly 30 ft. (hover)
Skills Perception +4
Damage Resistances cold, fire, piercing and slashing from nonmagical attacks that aren’t adamantine
Damage Immunities lightning, necrotic, poison, psychic
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, petrified, poisoned, prone, unconscious
Senses blindsight 60 ft., passive Perception 14
Languages understands the languages of its creator but does not speak
Challenge 5 (1,800 XP)

Special Traits

• Lightning Absorption. If the thunder orb receives lightning damage, it takes no damage and instead gains temporary hit points equal to the damage amount.

Actions

• Lightning. Ranged Spell Attack: +5 to hit, range 30/90 ft., one target. Hit: 14 (4d6) lightning damage.
• Grand Lightning (Recharge 5-6). Each creature in a line 100 feet long and 5 feet wide originating from the orb must make a DC 12 Dexterity saving throw. A creature takes 28 (8d6) lightning damage on a failed save, or half as much damage on a successful one. The lightning ignites flammable objects in the area that aren’t being worn or carried.

Reactions

• Free-floating. When struck by a melee attack, the thunder orb can move half its speed without provoking an opportunity attack.
• Relentless Defenders. Thunder orbs are magical constructs tasked with guarding vaults, tombs or other important places. It attacks anyone not allowed safe passage by its creator. Made by an arcane spellcaster by binding an elemental spirit into the orb, it will not retreat before superior foes. Indeed, the spirit trapped within knows that should the orb be destroyed, it will be released, free to return to its own plane.

Tactics

Thunder orbs rarely close with their opponents and if the party gangs up on one it will attempt to use its movement and its free-floating reaction to move away from the group, using its grand lightning if available. In more elaborate dungeons, two or more thunder orbs will guard an area, programmed so that when one uses its grand lightning, the others are in the line of fire so that they receive temporary hit points.

Description

Hovering a couple feet off the ground, this 4-foot diameter sphere of dark basalt stone crackles with electricity. Its stone surface is carved with arcane runes of confinement which seem to glow from a brighter source within the orb.