Orcas are known to be smart and ruthless hunters. They've been observed hunting a variety of prey, with some species, such as whales, larger than themselves. They use a wide range of strategies to hunt and kill prey, but now, in the Gulf of California, researchers have observed one that hasn't been described before.
The video in that link is absolutely crazy. It doesn’t even make sense that an animal body would do that.
My first thought was maybe it had been dead for awhile and was decomposing?
According to the article it was already dead, but I inferred that the orcas had killed it. The authors posit that perhaps this species of sunfish has a fleshy structure that makes this kind of explosive deconstruction possible.