Jammer leech

Jammer leeches were space parasites that fed on the magic channeled by the pilots of spelljamming helms.

Description
A typical jammer leech had a shell that could grow up to 1 ft (30 cm) tall. As the leech grew, its shell drew material from the hull it was attached to, which caused it to acquire the same color as the ship. This property made jammer leech infestations exceedingly difficult to detect.

Within the shell, a leech had a snail-like reddish-purple body with a single watery eye and a tentacle with sharp spikes at one end.

Jammer leeches did not require air to survive, so they could be found almost anywhere spelljammers existed. They fed by drawing magic from the pilot of a spelljamming helm. Over the course of ten days, each leech absorbed one random spell known to the pilot, who lost the ability to cast it and needed to prepare it again. To make matters worse, the caster only realized that the spell had been lost upon trying to cast it.

Behavior
Jammer leeches tended to prefer to attach themselves at locations on ships' hulls that were close to the spelljamming helm.

Combat
If faced with a threat, the first reaction of a jammer leech was to use its sharp tentacle. If that did not discourage the attacker, the leeches randomly released the spells they had consumed, a behavior that made them unpredictable and dangerous. The only safe way to deal with an infestation was to use dispel magic to discharge a leech before attacking it. Even so, the creature had a natural resistance to magic, so even that strategy was not entirely free of risk.

Ecology
Clusters of jammer leeches tended to consist of four or less individuals. They reproduced by releasing spores that could either attach to the hull of the same ship or drift through space to a nearby ship. Once attached, they drew material from the hull (incidentally, also damaging the hull) and converted it into their shells, which formed after about one week.

The material that kept jammer leeches attached to the hull was akin to a strong glue. Despite making the task of cleaning leeches difficult, the glue was very valuable due to its waterproof, fireproof, and magic-resistant properties.

Pickled jammer leeches were considered a savory delicacy. Crates were typically stored in Stardock for its githyanki inhabitants in the late 15 century DR.

Appearances

 * Waterdeep: Dungeon of the Mad Mage (mentioned only)