Giant Freshwater Stringrays are in fact dangerous to humans, but not because they eat them. These creatures actually feed on small fish and invertebrates. However, as their name might suggest, they have stinging barbs on their tails. These venomous, mucus covered barbs can grow to 15in (38cm) long, and with their whip-like tails, these Stingrays can pierce bone.
These enormous creatures are currently very vulnerable, and all populations are listed as at least that by the IUCN. The Thailand sub-population is Critically Endangered. They faces issues with habitat destruction, fishing, mine-caused silt deposits, and population fragmentation.