Book of Monsters at Hellspin Casino: cluster pays slot guide
Pragmatic Play's horror-themed 7x7 cluster pays slot delivers 96.50% RTP with high volatility and a 5,000x maximum win multiplier.
Book of Monsters: a 7x7 horror grid where clusters win
7x7 grid, cluster wins. Book of Monsters is a horror-themed cluster pays slot on a 7x7 grid released in March 2025 by Pragmatic Play. Winning clusters need 5 or more matching symbols touching horizontally or vertically, not along paylines. A random giant symbol (FAT symbol) can appear each spin, from 3x3 to 7x7 in size, creating instant wins. High volatility means wins come less often but can be much bigger. The slot combines standard spinning rounds with a buyable free spins bonus.
Who this slot suits. Book of Monsters suits players who enjoy high volatility slots and don't need frequent wins. The minimum bet starts at NZ$0.20, while you can play up to NZ$480 per spin. If you prefer regular payouts, the Ante Bet option (doubling your stake to NZ$20 on our example top bet) makes the bonus trigger 7 times more often. Players seeking massive potential wins will appreciate the x5,000 multiplier and NZ$2,400,000 maximum win at the highest bet.
When does the bonus begin? The Free Spins round is what transforms your session. You trigger it with 4 or more Bonus symbols (or 3 with Ante Bet active), or buy it for 100x your bet. During free spins, your chosen giant symbol grows larger as you collect more instances of it, and each size upgrade adds 1 to 3 extra spins. Before the round starts, a gamble screen lets you upgrade your giant symbol's tier or spin count, or take what you've earned and begin playing.
Full storyWhat are the odds and limits on Book of Monsters?
You'll know the game's payout rate, limits and win patterns before placing your first bet.
Pragmatic Play
NZ$2 400 000
From your bet to the payout: five steps
See exactly what happens between your first bet choice and when you cash out
Book of Monsters symbol payouts
These payouts apply at a NZ$5 bet. More connected symbols in your cluster mean higher winnings.
Top earners
Red Monster5+ NZ$5 · 49+ NZ$12 500
Green Monster5+ NZ$2.50 · 49+ NZ$1 250
Purple Monster5+ NZ$1.25 · 49+ NZ$625Lower symbols
Ace5+ NZ$1 · 49+ NZ$500
King5+ NZ$0.75 · 49+ NZ$375
Queen5+ NZ$0.62 · 49+ NZ$312.50From base game to Free Spins mode
How to start your bonus spins. 5 to 8 spins are awarded when 4 or more BONUS symbols land, or you buy them for 100x your bet. Your chosen FAT symbol starts at 1x1 and grows to 7x7 as you collect more instances. Each size increase awards 1 to 3 extra spins. Before the round begins, you can upgrade the FAT symbol tier, add spin count, or proceed.
Book of Monsters Ante Bet mode. Enable Ante Bet to multiply your stake by 2.0 and reduce the symbols needed to trigger Free Spins from 4 BONUS to 3 BONUS. This makes the bonus 7 times easier to reach. Ante Bet mode replaces the Buy Free Spins option, so you cannot purchase the bonus while it is active.
What you win without the bonus. The base game runs on a 7x7 cluster pays grid where 5 or more symbols touching horizontally or vertically form a win. A FAT symbol—a random block 3x3 to 7x7 in size—may land on any spin. When symbols cluster around it or land within it, both the cluster and the FAT symbol pay from that same spin.
Full storyJump straight to the bonus
Skip to Free Spins instantly for NZ$1,000 at a NZ$10 bet. Buying spins means you avoid waiting for 4 bonus symbols to land, though the outcome of each spin stays unpredictable.
Bonus symbols land more often
Double your stake to NZ$20 per spin and Free Spins trigger at 3 bonus symbols instead of 4. Ante Bet stays active for the whole session and stops the buy option working.
What cannot be predicted about Book of Monsters?
When does the bonus arrive? When the bonus round arrives is entirely random. No pattern, timing or stake choice affects how often it triggers. Your session may include many bonus rounds or none.
Short-term results are random. One session's result is pure chance. The 96.50% RTP describes what happens across thousands of players over time, not what happens to you in one sitting or week.
Theory meets reality on maximum wins. The NZ$2,400,000 maximum win is a theoretical ceiling, reached only once in countless spins. You will not see it. Plan to play within what you can afford to lose.
Full storyTry Book of Monsters free or play for real
Play the demo to learn how clusters work, then switch to real money whenever you're ready.
Every 100 you stake: 96.50 returns to you
RTP is the average return over a very large number of spins. The 96.50% figure applies across the standard game, when you use Ante Bet, and when you buy Free Spins—each condition uses this same long-run rate.
RTP 96.50% · Standard game, Ante Bet, or Buy Free Spins
What you need to know about Book of Monsters
Straight answers about how this slot works and what to expect.
Can I play Book of Monsters in demo mode without real money?+
Can I see the RTP of Book of Monsters before I play?+
What happens if Book of Monsters is volatile?+
What if I land the top win on Book of Monsters?+
Why set boundaries before you play?
Before you spin: choose your spend. Decide how much you can afford to lose on Book of Monsters before you start playing. This amount should be money you're comfortable spending like any other entertainment without affecting your bills or savings.
Decide your exit point early. Choose in advance when you'll stop, whether you're ahead or behind. A big win can feel like a reason to keep playing, but a planned stopping point keeps your session under control.
Book of Monsters: use account controls. Use your account's deposit limits and loss limits to control how much you spend across all games. These tools give you real barriers that help you stick to the budget you set.
Stop playing if it stops being fun. If Book of Monsters or any game stops being fun and starts feeling urgent, take a break or use self-exclusion. The Problem Gambling Foundation of New Zealand and Gambling Helpline New Zealand offer free support.
Full story