“In this Smash Bros. installment, this little guy is also making an appearance! I…don’t know his name, but he’s the Prince of the Sablé Kingdom. He’s from the Game Boy game Kaeru no Tame ni Kane wa Naru (translated as The Frog For Whom the Bell Tolls), which was only released in Japan.
Here’s the trophy of the Sablé Prince. He transforms into a snake or a frog, and unloads multiple attacks on any opponent he catches. Keep attacking your foes when they’re trapped in his dust cloud.” - Masahiro Sakurai