Boo

"Boo" by Big Time Gaming is a classic video slot on a 4-row and 4-reel grid with 256 ways to win. The design follows a spooky Halloween theme with ghosts, pumpkins, and haunted house atmosphere. In the base game, there are wild symbols that appear only on reels 2, 3, and 4; these wilds can have multipliers of up to x4, which multiply when multiple wilds are involved in a win. Once a win is achieved, the reaction mechanic (cascading reels) is activated: winning symbol(s) disappear and are replaced by new ones, allowing for chain reactions.

With at least three scatter symbols (pumpkins), the free spins feature is triggered: there are 12 free spins, and all positions on the playing field receive consistent multipliers that can grow during the feature. The positions of the triggering scatters start with multipliers (e.g., x2 to x4), while all others usually begin at x1. With each win from ghost or wild symbols, the multiplier on one or more positions increases by +1, +2, or +3. If the feature is triggered again with additional scatters (retrigger), extra free spins are added along with a multiplier increase.

A bonus buy feature allows players to jump directly into the free spins feature: either with 12 free spins or a premium variant with 24 free spins. Depending on the purchase, the winning potential also increases significantly. "Boo" features high volatility, resulting in large swings, especially during the free spins — the game rewards patience and risk-taking bets with the chance for very high wins.

You can play it for real money.