The Mysterious PlayStation Vita Dolphin Test Screen
You'll hopefully never see low poly dolphins on your new hardware.
As with any new hardware, there are various reports out there about screen freezes, bugs and other issues with PlayStation Vita.
Here's a more serious issue: a Vita that's stuck in what appears to be a debug mode.
There's no way to tell if this is legit or not (although it would be quite a lot of work for a hoax), but if you do see some low polygon dolphins swimming on your Vita OLED screen, you should probably contact Sony customer support (or put your system up on Ebay).