Mustang Trail Slot by Pragmatic Play

The base game runs a random wild mechanic that triggers every time a wild symbol lands on the reels. When it does, additional wilds are scattered across random positions on the grid - sometimes just one or two, sometimes enough to fill most of a reel. It turns otherwise dead spins into something worth watching.

Free spins start with 8 rounds on a special set of reels. Scatter symbols, which only appear on reels 1, 3, and 5 during normal play, now show up on all five reels. Each scatter that lands gets collected into a meter. Every third scatter collected does two things: it retriggers the feature with 5 extra spins, and it permanently pins a new wild to a random reel position for the rest of the round. The wilds don't disappear between spins - they stack up.

By the end of a long free spins session, the grid can be loaded with fixed wilds across multiple reels, turning nearly every spin into a guaranteed payout. The buy option costs 50x total bet and jumps straight into those 8 starting spins.

Symbol pays are steep for a 10-line game. The top horse symbol and the wild both pay 150x total bet for five of a kind. The ram sits at 75x, buffalo and lizard at 50x each, and six card ranks share the bottom tier at 10x for five.