Spined Shard

Few things are as feared as the spined shard in the borderland where the Positive Material Plane meets the Quasi-Plane of Mineral. It is equally comfortable deep in pure positive energy, which it absorbs, and among the crystal reaches of Mineral, where it hunts.

Highly intelligent and extremely cunning, the spined shard has a surface so hard that it can be harmed only by weapons enchanted to +2 or more. Lesser weapons that touch it melt automatically, and +1 weapons have a 50% chance of melting too. It constantly projects a 10-foot field of heavy magical interference that works as a limited antimagic shell, ruining any spell cast into it 75% of the time.

It lashes out with four small whiplike tentacles for 1d4 each. If two or more hit the same foe, the victim is seized automatically and pulled to its two doublewhip stingers, which strike a held victim at +4 for 2d6 energy damage apiece.

Its most feared weapon is a set of four energy bursts per day, fired as tight one-inch beams from its four radial spines out to 75 feet. Each hits a single target for 8d8 damage, avoided entirely with a save vs. spells. The victim keeps half that energy for one turn, and any living creature coming within 5 feet in that time draws an arc for 4d8 damage, halved by a successful save vs. paralysis. Those struck by the arc do not carry a further charge.

The spined shard is spiteful and kills without reason, even tearing into whole swarms of shards to feed on their stored energy. Anything within 90 feet risks immediate attack. Badly hurt, it tries to seize a foe and, a round later, carry it away by plane shift into the depths of positive energy.

Powerful wizards sometimes summon spined shards to guard especially potent magic items. This takes great care: a summoner lacking the right protections is attacked instantly.