Mjolnir is present as a goal element on some levels. You won’t see it at first – because you need to produce it in the mold.

A mold first appears sealed with a metal lid. You need to break the lid, but you only can do so by directing power-ups at it.

Once the lid is broken, matches made next to the mold start working, too. It now takes 6 more hits, to for the Mjolnir to be released. Each consecutive match fills the mold with glowing steel, until the final strike completes the forging.
Then Mjolnir gets released from the mold, lands on the field and launches a cross-shaped blast. The blast reaches from one end of the board to the other, both horizontally and vertically. It brings damage to every element in its path, and can activate power-ups.

Mjolnir is counted towards the level goal, after the hammer strikes.