A nine-year-old boy recently died from primary amoebic meningoencephalitis, which is caused by an amoeba called Naegleria fowler.
The deadly little guy prefers to live in warm freshwater, like that of a summer lake.
Once there, it begins eating the brain, causing serious inflammation.
Even if caught early (which it rarely is) and treated, death can still occur within two weeks!
Swimming has been banned at Lily Lake in Stillwater Minnesota after it was found that the boy swam there and the amoeba lives there.
Check out the video (above) to find out what they're doing about this awful, scary situation.