The reason why price went back down is because there is huge resistance and supply at the $350 area and today there aren't many market participants because its the weekend.
One whale alone can't move the market past $500. Don't trade on weekends with no liquidity.
The reason it went crashing back down, was because the whale pushed Bitcoin high enough to trigger a bunch of Stop Orders, into which he would no doubt have been mass selling and when that burst had run out of juice, he dumped the remainder of what he had acquired from the pump.
There may well be large resistance at $350, but it would have been broken through, had this whale had the desire to see the market go that way. The big players can pretty much manipulate this market anyway they want, sell where they want, and buy where they want. Bitcoin is a trading shark's wet dream.