Merlin is one of the mascots from the "Medieval" section in Crossy Road. Although a completely different mascot, Merlin is similar to "Mad Wizard".
Merlin cannot be unlocked from the Prize Machine using 100 coins. Instead, Merlin is a secret mascot that can only be unlocked using the "Wart".
To unlock Merlin, the player has to use the Wart, and encounter a big patch of land. The big patch of land is the one that is found by other characters where many coins, and birds are sitting around. When the big patch of land is found by the Wart, though, there will be a sword in a big rock, as a reference to the Excalibur. There will also be a shining effect all around the screen and a shining-type sound as well. When the player approaches the rock, the sword will be automatically pulled out, although no animation from the mascot. Finally when the player dies, Merlin will be unlocked.
Just like how the Mad Wizard has an easter power of zapping lightning to near by plants and trees, Merlin also has an power. If the player stops moving, after about one second, all the items in a certain radius will be slowly levitated/lifted. While this is happening, the blue globe at the top of Merlin's staff will also glow brightly. When the player moves/hops again at any time, the blue globe will stop glowing and the items will drop down.