Poeobius is a genus of marine polychaete worm.

It contains the single species Poeobius meseres, or balloon worm.

[1][2] This is a common and abundant resident in the midwater around the mesopelagic and bathypelagic zones, especially in Monterey Bay.

[3] They can be found at around 300-2,500 m (980-8,200 ft) depth from Japan to Alaska to the Gulf of California, and have also been reported in South America.

[3] The species is a passive detritivore, using a mucus net to capture marine snow as it hangs neutrally-buoyant midwater.