A Spellseeker appears as a cluster of 1D4 large eyes held together with a cancerous looking constantly moist flesh. These large eyes can be six to eight inches across. The creature also has jellyfish like tendrils that hang from it, and it drifts on unseen currents, seemingly unbothered by the environment around them.
The Spellseeker is drawn to magic, magic users, and magic items. This can make them useful as trackers. When they find something magical, they will batten onto it and start feeding from it. Areas of magic power can foster large populations of spellseekers. They will fight each other over magic swords, and will bind themselves to golems and other magical creatures.
Sense Magic - they can detect magic and will move towards it.
Drain Magic - A spellseeker can drain a small amount of magic with a physical attack. This can remove spell potential from magic users, lower the local power level, or even drain items, but this takes time.
Duplication - after draining enough magic power, a spellseeker grow a new large eye, or it can bud on existing eye off and create a new spellseeker.
Confrontation and Combat
Fighting a spellseeker is can be a difficult prospect. They are borderline intangible, and can only be harmed by magic weapons and magical attacks. They have almost no hit point, but have a very high evasion ability and will seemingly flow out of the way of attacks that can harm them. The most effective attacks deal area damage, or have a swarm component that the spellseeker can't evade all of. The difficult thing about fighting spellseekers is that they never really have to be fought, aside from their draining power, they cannot inflict damage, and can barely affect the material world around them.
Spellseekers can be used as magic scenting hounds, especially if searching for a weak magic item, or a concealed one.
In a dungeon scenario, the spellseekers can be used as a distraction. They resemble beholders, and the PCs could unload heavy firepower on them, depleting their abilities before the next encounter. Being trackers, a group of PCs could find themselves being followed by several of these harmless creatures, which consistently give their position away. This can allow for other dungeon monsters to spot wizards and magic item bearers.