X-Demon Bonus Buy Slot by Evoplay

A hidden extra row sits above the five reels. Wild Attack symbols land exclusively on that top row, and when one appears directly above a demon, it zaps the demon and converts it into a Wild for that spin. Since the top row sits outside the 20 paylines, the Wild Attack itself never forms part of a winning combination - it only serves as a trigger.

Free spins bring a collection mechanic into play. Each of the six demon types has its own meter tracking how many more hits it needs. Every time a Wild Attack converts a specific demon during free spins, that demon's counter drops by one. Complete a meter and the demon permanently turns into a Golden Wild for all remaining spins, plus 2 extra free spins are added. Filling multiple meters stacks Golden Wilds across the reels, which is where the bigger payouts come from.

The base version of X-Demon lacks a buy bonus option, but this Bonus Buy edition adds three tiers: 8 free spins at 30x bet, 10 at 52x, or 12 at 86x. More starting spins means more chances to fill demon collection meters before the round ends. The top two demon symbols both pay 150x per line for five of a kind, so even partial meter completions combined with Wild Attacks produce solid returns on the 20 paylines.