Book of Monsters Slot by Pragmatic Play

Fat Rabbit's Weird Cousin

Book of Monsters drops a 7x7 cluster pays grid into a cave full of cute, goofy monsters. Pragmatic Play borrowed the growing-symbol concept from Push Gaming's Fat Rabbit and layered it onto a book-style trigger with a gamble phase. The result is a slot that doesn't fit neatly into any category, which is both its strength and its problem.

Cluster pays require minimum 5 matching symbols connected horizontally or vertically. Seven monster symbols handle the premium end, with the top monster paying 40 coins for a 5-cluster and scaling all the way to 100,000 coins if you somehow fill all 49 positions. Card royals (J, Q, K, A) sit at the bottom. The 96.50% RTP holds across regular, ante, and buy modes.

FAT Symbols in Base and Bonus

Even in the base game, oversized symbols appear randomly: 3x3, 4x4, 5x5, 6x6, or a full 7x7 block covering the entire grid. These are the same paying symbols, just bigger. A 5x5 block of the top monster creates a 25-symbol cluster in one shot, which pays 1,200 coins before the surrounding grid is even counted.

The real action is in free spins. Trigger with 4 or more Bonus symbols (3 with the ante bet active) and the game assigns a random paying symbol as your designated FAT symbol for the round. The FAT symbol starts at 1x1 and roams to a different random position each spin.

The Growth Grind

Every instance of your FAT symbol type that lands elsewhere on the grid gets collected into a meter. Hit 30 and the FAT grows to 2x2. Collect 27 more for 3x3. Then 24 for 4x4, 20 for 5x5, 16 for 6x6, and 12 for 7x7. Each growth awards 1 to 3 bonus spins.

The math here matters. Growing from 1x1 to 7x7 requires collecting 129 total symbols across the round. That's a lot of spins. Most rounds won't reach the maximum size, and a low-value symbol assigned as your FAT makes those clusters less valuable even at large sizes. The gamble phase before the round starts exists to address this.

Gamble or Collect

After triggering free spins, the game randomly picks your FAT symbol and starting free spin count. You can collect immediately or gamble. Each gamble attempt risks the entire feature: win and your FAT symbol upgrades to the next higher-paying symbol (or you gain extra spins), lose and you walk away with nothing. The odds are displayed in-game, so the risk is transparent.

Gambling up to the top monster as your FAT symbol turns every cluster into a premium payout. But if the book lands on a blank page, the feature vanishes. It's a genuine all-or-nothing decision that separates this from most Pragmatic Play slots.

Ante Bet Trade-Off

The ante bet doubles your stake from 20x to 40x per spin and gives seven times higher chance to trigger free spins, lowering the Bonus requirement from 4 to 3 symbols. It also disables the Buy Feature (100x), so you can't stack both shortcuts. The ante is aggressive - doubling your bet for a trigger boost only makes sense if you're specifically chasing the feature.

Base game is quiet. Around one win every four spins from the cluster system, and the oversized random symbols create occasional bursts. But without the growing FAT mechanic, those clusters don't escalate. The 5,000x cap is modest for a 7x7 grid, and reaching it requires either a fully grown 7x7 premium FAT symbol or an extremely lucky cluster arrangement.