Special Symbol
Area Symbol Transformation
A feature where a random symbol on the grid is selected as a "Marked Target," and all symbols within a 3x3 or 5x5 area surrounding it transform to match that target symbol.
Special Expanding Symbol
A popular feature that expands in a unique way
The Special Expanding Symbol is one of the most iconic and popular mechanisms in online slot history, a core free spins feature primarily found in 'Book of...' series games.
The essence of this feature is that one regular symbol, randomly selected at the start of the free spins, gains a special power. This symbol, as long as it appears on the reels in the required number to form a win, will expand to cover its entire reel and create massive wins regardless of its position.
More Features in This Family
Special Symbol
Bonus Overlay Symbol
A feature where a special effect is overlaid on a regular symbol, which then awards a special bonus (e.g., free spins).
Special Symbol
Cash Symbol Cloning
A feature where existing cash symbols clone their values onto adjacent empty positions, multiplying the total collectable prizes.
Special Symbol
Cluster Merge & Level Up
A dynamic mechanic where winning clusters merge and transform into higher-level symbols, driving continuous progression.
All Slots with This Feature
Preview
Mystic Aztec is a Aztec-themed slot by Vivid Gaming. The slot is built on a 5x3 reel grid with 10 paylines and offers a theoretical maximum win of x1,500. It also comes with special features such as Special Expanding Symbol and Persistent Symbol, adding extra gameplay variety from the feature mix and extra gameplay variety from the feature mix.
Preview
Book of Dizzy is a dark magic wizard's library-themed slot by Degen Studios. The slot is built on changeable reels with 10-20 paylines and offers a theoretical maximum win of x10000x. It also comes with special features such as Special Expanding Symbol and Reel Expansion, adding extra gameplay variety from the feature mix and expanded reel space during key moments.
300SPINS™
casual+
Wicked Grin is a macabre cartoon-themed slot by Hacksaw Gaming. The slot is built on an irregular reel setup with cluster pays and offers a theoretical maximum win of x10000x. It also comes with special features such as Cascading Reels and Special Expanding Symbol, adding repeat-win chances from cascading symbol drops and extra gameplay variety from the feature mix.
Preview
Big Wiz is a wizard-themed slot by Playnetic. The slot is built on a 5x3 reel grid with 10 paylines and offers a theoretical maximum win of x25,000. It also comes with special features such as Multi-Function Symbol and Random Trigger, adding symbol transformations that change the round shape and surprise changes to the spin flow.
Preview
9K Wild Yeti Dream Drop is a arctic yeti-themed slot by 4ThePlayer. The slot is built on a 5x3 reel grid with 1,024 ways. It also comes with special features such as Progressive Jackpot and Stacked Symbol, adding extra jackpot targets alongside regular wins and extra gameplay variety from the feature mix.
Preview
Book of Aferist is a pirate-themed tropical adventure slot by TrueLab. The slot is built on changeable reels with 1-10 paylines and offers a theoretical maximum win of x12,000. It also comes with special features such as Multi-Function Symbol and Special Expanding Symbol, adding symbol transformations that change the round shape and extra gameplay variety from the feature mix.
Preview
Scroll of Gods is a ancient Greek mythology-themed slot by Playnetic. The slot is built on a 5x3 reel grid with All Ways and offers a theoretical maximum win of x8,000. It also comes with special features such as Multi-Function Symbol and Special Expanding Symbol, adding symbol transformations that change the round shape and extra gameplay variety from the feature mix.
Preview
Book of Magic is a wizard and magic-themed slot by Zillion Games. The slot is built on a 5x3 reel grid with 25 paylines. It also comes with special features such as Hold and Respin and Fixed Jackpot, adding locked-symbol bonus tension and extra jackpot targets alongside regular wins.
Preview
Book of Hidden Tombs is a Egyptian-themed slot by BGaming. The slot is built on a 5x3 reel grid with 10 paylines and offers a theoretical maximum win of x10,000. It also comes with special features such as Special Expanding Symbol and Accumulating Multiplier, adding extra gameplay variety from the feature mix and multiplier-driven win scaling.
The information provided by SlotWise, including reviews, guides, and analysis, is for informational and entertainment purposes only.
All data is based on our own 300-spin tests and is not a guarantee of future results.
Please gamble responsibly and within your means.
This site is intended for users aged 19 and over.
ⓒ SlotWise, 2025, All rights reserved
Comments
No comments yet. Be the first to comment!