Book of Monsters by Pragmatic Play offers a unique monster-themed experience on a 7×7 grid where symbols pay in connected blocks rather than traditional paylines. The slot features three colorful monster characters as premium symbols alongside card royals, all designed with vibrant cartoon aesthetics. During the innovative free spins feature, a randomly selected FAT symbol progressively grows from 1×1 up to potentially 7×7 as players collect matching symbols, with each size increase awarding additional spins. With high volatility (5/5) and 96.50% RTP, the game balances significant win potential up to 5,000x bet with strategic elements including a pre-bonus gamble system. Players can opt for an Ante Bet to increase trigger frequency or use the Buy Feature option at 100x bet for immediate access to free spins.
Book of Monsters by Pragmatic Play introduces players to a uniquely engaging monster-themed slot experience played on a 7×7 grid. Unlike conventional slot games, this creation focuses on connecting symbol blocks rather than traditional paylines. The game captures attention with its colorful monster characters and innovative “Fat Symbol” mechanic during the free spins feature.
Game Symbols and Paytable Overview
The paytable reveals a hierarchy of symbols with varying values. The highest-paying symbols are the three monster characters – red, green, and purple blob-like creatures with distinctive personalities and expressions. The red monster offers the most substantial rewards, paying up to $10,000 for 49 matching symbols. The green monster follows with payouts reaching $1,000 for the same quantity, while the purple monster offers maximum rewards of $500.
Lower-value symbols include the card symbols A, K, Q, and J, designed with a glowing neon aesthetic against blue backgrounds. The paytable clearly demonstrates the exponential value increase as more matching symbols connect, encouraging players to aim for larger symbol blocks.
The BONUS symbol, depicted as a golden book with monster eyes, serves as the scatter symbol. Landing 3 to 7 of these symbols triggers the Free Spins feature with corresponding spin awards ranging from 4 to 8 free spins (when using Ante Bet) or 5 to 8 free spins (during standard play).
Core Gameplay Mechanics
The fundamental gameplay in Book of Monsters diverges significantly from traditional slot formats. The 7×7 grid allows for expansive symbol connections, with the game rewarding players for creating blocks of at least 5 identical symbols connected horizontally or vertically.
During the base game, an interesting random feature can activate on any spin, where symbol blocks of varying sizes (3×3, 4×4, 5×5, 6×6, or 7×7) can appear spontaneously. This random element adds unpredictability to each spin and creates opportunities for substantial wins without entering bonus rounds.
The game calculates wins based on the highest value combination, with multiple winning blocks added together for the total win. All values displayed represent actual coin wins multiplied by the base bet, making win potential transparent for players.
The betting range accommodates various player budgets, starting from a minimum bet of $0.20 and extending to a maximum of $480.00. This wide range makes the game accessible to casual players while simultaneously appealing to high rollers seeking substantial win opportunities.
The Innovative Free Spins Feature
The Free Spins feature represents the centerpiece of Book of Monsters, incorporating several innovative elements that distinguish it from typical bonus rounds in other slots. Triggered by landing 4 to 7 BONUS symbols (or 3 to 7 when using Ante Bet), the feature initially awards 5 to 8 free spins respectively (or 4 to 8 with Ante Bet).
Upon triggering the feature, players encounter a unique gamble mechanic. Before the free spins begin, the game randomly selects one paying symbol to become the “FAT symbol” for the round. Players then face strategic choices:
Gamble options are gamble to upgrade the FAT symbol to a higher-value symbol, gamble to increase the number of free spins and collect the current FAT symbol and free spins to begin the round. The gamble system works through a book animation where pages turn to reveal either the improved symbol/additional spins or “THE END” (indicating a lost gamble and the end of the feature). The game displays win probabilities for each gamble option, allowing for informed decision-making based on current free spins and the selected FAT symbol.
Players can gamble up to reaching either 8 free spins or the highest-value symbol as the FAT symbol. This risk-reward system adds a strategic layer to the game, allowing players to potentially enhance their bonus round before it begins.
Progressive FAT Symbol Growth System
The most distinctive aspect of Book of Monsters is its progressive FAT symbol growth system during free spins. When the round begins, a 1×1 FAT symbol appears on the screen, randomly moving to a new position with each spin.
The game implements a collection mechanic where instances of the selected FAT symbol that appear during spins (and aren't overlapped by the FAT symbol itself) are collected in a meter. As players reach specific collection thresholds, the FAT symbol grows in size:
- 30 collected symbols: FAT symbol grows to 2×2
- 27 more collected symbols: FAT symbol grows to 3×3
- 24 more collected symbols: FAT symbol grows to 4×4
- 20 more collected symbols: FAT symbol grows to 5×5
- 16 more collected symbols: FAT symbol grows to 6×6
- 12 more collected symbols: FAT symbol grows to 7×7
Each size increase randomly awards 1, 2, or 3 additional free spins. The expanding FAT symbol creates increasing win potential as the feature progresses, with the ultimate goal of reaching the maximum 7×7 size that covers the entire grid.
Special reels are also in play during free spins, further enhancing the bonus experience. This progressive system creates mounting excitement as players collect symbols and witness the FAT symbol's growth throughout the feature.
Additional Game Features and Betting Options
Book of Monsters incorporates several additional features that enhance gameplay flexibility:
Ante Bet: Players can select from two bet multiplier options: 40x multiplier: Reduces the minimum BONUS symbols needed to trigger free spins from 4 to 3, increasing trigger frequency by seven times. However, this option disables the Buy Free Spins feature. 20x multiplier: Standard gameplay with normal trigger requirements.
Buy Bonus: For players seeking immediate access to the free spins feature, the game offers a Buy Bonus option. By paying 100x the current total bet, players can instantly trigger the free spins round. The triggering spin will randomly include 4 to 7 BONUS symbols.
Win Cap: Both the base game and free spins include a maximum win cap of 5,000x the bet. If this threshold is reached during free spins, the round ends immediately, awarding the win up to the cap and forfeiting any remaining spins.
Visual Design and Thematic Elements
Book of Monsters presents a vibrant, cartoon-style monster theme with distinctive character designs. The three primary monster symbols feature expressive faces with exaggerated features – wide mouths filled with sharp teeth, bulging eyes, and colorful blob-like bodies in red, green, and purple.
The card symbols (A, K, Q, J) maintain thematic consistency through neon-colored designs against blue backgrounds, creating a cohesive visual identity. The BONUS symbol incorporates the monster theme through a golden book with animated eyes, reinforcing the playful monster aesthetic.
The overall visual design creates an accessible, light-hearted atmosphere that contrasts with the high volatility gameplay. This juxtaposition of friendly visuals with high-risk mechanics creates an interesting psychological dynamic for players.
Strategic Considerations for Players
For experienced slot players approaching Book of Monsters, several strategic considerations emerge:
Ante Bet Evaluation: The 40x multiplier option significantly increases free spins trigger frequency by reducing the required BONUS symbols from 4 to 3. However, this comes at the cost of disabling the Buy Bonus option. Players must weigh immediate access (Buy Bonus) against increased natural trigger probability (Ante Bet).
Gamble Decision Points: During free spins, the decision to gamble for a better FAT symbol versus additional spins involves risk assessment. Generally, upgrading to a higher-value FAT symbol offers greater long-term potential if successful, while additional spins provide more opportunities for collection and expansion.
Collection Focus: During free spins, maximizing collection opportunities becomes critical. Each expansion threshold represents a significant increase in win potential, with the 7×7 FAT symbol covering the entire grid representing the ultimate goal.
Win Potential vs. Risk: With a win cap of 5,000x bet, players should recognize that the game balances substantial win potential with high volatility risk. Bankroll management becomes particularly important given the extended periods without significant wins that high volatility can produce.
Book of Monsters delivers a distinctive slot experience through its combination of block-pay mechanics, progressive collection system, and strategic gamble options. The FAT symbol growth mechanic creates a clear progression path during free spins, generating anticipation with each collection milestone. The game's 96.50% RTP remains consistent across all betting options, providing fair returns regardless of player approach. The high volatility (5/5) clearly signals the game's risk profile, allowing players to make informed decisions about engagement. For experienced players seeking fresh mechanics beyond traditional payline slots, Book of Monsters offers genuine innovation through its expanding FAT symbol system and collection-based progression. The strategic gamble options add meaningful player agency rarely seen in standard slot games. While the maximum win cap of 5,000x bet may be lower than some competitor offerings, the clear progression path and strategic elements provide compensating engagement factors that distinguish this title within Pragmatic Play's portfolio. The game successfully balances accessibility (through its vibrant visuals and straightforward core mechanics) with depth (through its progressive collection system and strategic gamble options), creating an experience with broad appeal while offering sufficient complexity for veteran slot enthusiasts.
