Cauldron

Yggdrasil's Cauldron is a video slot featuring 5 reels and 3 rows, offering 20 fixed paylines set against the backdrop of a mysterious magical workshop filled with potions, pests, and wizardry. Wild symbols can only be found on reels 2, 3, and 4, acting as substitutes for all standard symbols except for the Scatter. Players gather Scatter potion-bottles in a meter located next to the reels; collecting three or more in a single spin activates the Free Spins mode, which begins with ten Free Spins. During this Free Spins feature, any win involving a high-value symbol results in that symbol being upgraded, allowing future wins with it to pay double, and each upgrade also grants an additional Free Spin. In contrast, winning with a low-value symbol leads to its removal from all following Free Spins while also providing an extra spin. Achieving a total of 750 Scatters unlocks a Super Free Spins round, where all low-value symbols are eliminated from the reels and all high-value symbols start with 2× multipliers. The game does not include a Bonus Buy feature, and the maximum potential win stands at 2,222× the bet.

You can play it for real money.