Thunder Bison: Lock the Coins and Let the Herd Charge

Storm over the prairie

Lightning cracks around a charging bison with golden horns and a cowbell on a leather collar, and coins fly off in every direction. That is Big Bo, the hero of Thunder Bison, and he spends the game beside the reels snorting, stomping and charging whenever something lands. Nocturn Play set the slot at dusk on an open prairie, with drums and thunder in the soundtrack.

243 ways and the base game

The board is five reels by three rows with 243 ways: symbols pay on adjacent reels from the leftmost reel, in any row. The eagle, wolf, elk and rattlesnake are the premium symbols, while the horseshoe, cowbell, feather and arrowhead fill the lower rungs. The wild appears on reels two, three and four and replaces every symbol except the storm cloud and the coins.

The real interest lies in the Thunder Coins. Each carries a cash value from 1× to 20× the bet, or one of three fixed prizes: MINI (10×), MINOR (25×) or MAJOR (100×).

Hold & Win

Six or more coins start Hold & Win. The coins lock, the other cells spin alone, and you get three respins. Every new coin resets the count to three. When the respins run out, every coin on the board pays. Fill all fifteen cells and the GRAND prize (1,000×) is added on top.

The Stampede Column

This is the signature twist. When a column fills with three coins, the herd charges across the board and lightning strikes. The values of every coin on the board, all three rows, are gathered into one super coin in the middle of that column, and its top and bottom cells open up again. Each column can stampede once per round. The effect is double-edged in an interesting way: you lose two locked cells but gain two fresh chances to land coins, and the super coin keeps the total. A round can pay at most 5,000 times the bet.

Free spins and the bonus buy

Three, four or five storm clouds award 8, 10 or 12 free spins, played on reels with more wilds and more Thunder Coins. Three or more clouds during the feature add five spins.

The bonus buy starts Hold & Win directly with six coins for 51.5 times the bet. In the Thunder Bison demo this is paid in virtual credits, so you can trigger it repeatedly and watch how the stampedes play out.

Testing tips for the free version

• Spin 150 or so base rounds at a small stake, around the equivalent of 20p, and count how often five coins appear without the sixth.
• During Hold & Win, keep an eye on which column is closest to full; a stampede there reshapes the board.
• Buy the feature five or six times rather than once, since a single Hold & Win varies enormously.

You can play Thunder Bison free with no download and no sign-up, in portrait or landscape on a phone, or on desktop. When you are ready for real stakes, the same game runs for real money at the casinos listed below.