Crystalline Form. The block can move through a space as narrow as 5 feet wide without squeezing. In addition, it can enter another creature's space and end its turn there.
Transparent. Even when the block is in plain sight, it takes a successful DC 15 Wisdom (Perception) check to spot it. A creature that tries to enter the block's space while unaware of it must make a DC 15 Dexterity saving throw. On a failed save, the creature enters the block's space.
False Appearance. While the block remains motionless, it is indistinguishable from a normal crystalline formation.
Multiattack. The block makes two crystal shard attacks.
Crystal Shard. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage. If the target is a creature, it must succeed on a DC 14 Constitution saving throw or become gradually crystallized. On a failed save, the creature is restrained as crystalline growths spread across its body. The creature must repeat the saving throw at the end of each of its turns. If it successfully saves three times, the effect ends. If it fails three saves, the creature is completely crystallized and preserved within the block's matrix.
Engulf. The block moves up to its speed. While doing so, it can enter Large or smaller creatures' spaces. Whenever the block enters a creature's space, the creature must make a DC 14 Dexterity saving throw. On a failed save, the creature takes 10 (2d6 + 3) slashing damage and is engulfed. The engulfed creature can't breathe, is restrained, and takes 21 (6d6) slashing damage at the start of each of the block's turns. When the block moves, the engulfed creature moves with it. An engulfed creature can try to escape by taking an action to make a DC 14 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the block.
Crystal Burst (Recharge 5-6). The block releases a burst of crystalline shards in a 20-foot cube. Each creature in that area must make a DC 14 Dexterity saving throw, taking 21 (6d6) slashing damage on a failed save, or half as much damage on a successful one. Any creature that fails its save by 5 or more becomes partially crystallized and is restrained until the end of its next turn.
Crystalline Shift. The block can rearrange its crystalline matrix, becoming resistant to one damage type of its choice (except force) until the start of its next turn.
Description
At first glance, this creature appears to be a gelatinous cube - a transparent cubic form drifting through dungeon corridors. However, closer inspection reveals its "gelatinous" form is actually composed of countless interlocking crystalline sheets that flow and shift with an unsettling geometric precision. Within its crystalline matrix, previous victims can be seen perfectly preserved, their forms fractalized into countless mirrored reflections.
Behavior
The block drifts through dungeons seeking items of interest - particularly magical artifacts, precious gems, and unique specimens. Rather than simply dissolving everything it encounters, it uses its crystalline matrix to perfectly preserve chosen items while its sharp edges disintegrate unwanted material. Some sages theorize the blocks may be gathering these preserved specimens for some unknown master or purpose.
Origins
Cellaphanous blocks were created by ancient artificers who sought to improve upon the simple gelatinous cube. By infusing crystals with transmutation magic and elemental essences, they created these more intelligent and methodical dungeon cleaners. Unlike their mindless ooze cousins, cellaphanous blocks are selective in what they preserve and destroy.
Treasure
When a cellaphanous block is destroyed, 1d4 perfectly preserved valuable items can be recovered from its matrix. Roll on the following table for each item:
- Gemstone (worth 100-1000 gp)
- Magic item (roll on Magic Item Table B)
- Preserved specimen (rare creature part worth 200-800 gp to the right buyer)
- Ancient artifact (non-magical but historically valuable, worth 300-1200 gp)
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