So they did some kind of experimental thing with the first stage off the coast of california. Not officially acknowledged during the webcast, but you could hear the callouts. I'm guessing they splashed it into the water deliberately, but I could be wrong. I think they're testing the interstage for Block 5 next year and making sure the new components all work well, though this is a Block 3 rocket and isn't designed for easy reuse the way the new Block 5 will be (which is why they're not bothering to try to recover it).