GREENVILLE, Mich. -

Officials say freshwater jellyfish-like creatures are turning up in a West Michigan lake.

The Daily News of Greenville and WOOD-TV report 14-year-old Alec Martinez and his 13-year-old brother Trenton recently spotted them in Como Lake in the Greenville area. They captured some of the roughly quarter-sized creatures, took photos and released them back into the lake.

The state Department of Natural Resources says the creatures don't sting and are relatives of actual jellyfish. The department says they don't pose a threat to swimmers.

DNR Fisheries Division Manager Jay Wesley in Plainwell says the creatures sometimes show up one year in a lake and then aren't found in the same lake for another 15 years. They're considered native to Michigan and the DNR says they're often found in southern Michigan.