The idea has been around for years but was brought up again this recently when the Washington Post interviewed biologist Mark Laidre, who captured footage of a coconut crab catching and dismembering a bird.
He went in search of the invertebrates after hearing a story about their power in 2014. “An adult red-footed booby had landed near the entrance to a coconut crab’s burrow,” Laidre told the paper, recounting the tale. “As the bird stood there, the crab slowly emerged from its underground lair, approaching the bird from behind. The crab then grabbed the bird by one leg and dragged it, struggling, back into its burrow.”
It took Laidre a while to capture footage that corroborated the story he'd heard, but he finally managed it in February 2016. Watching the video of the crab and the bird (which is below, and is definitely not for the faint of heart) it's not hard to imagine see how a number of them could do some serious damage to a human body. If you do take a look, you may never look at crabs the same way again.