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Slot Features · Casimo Glossary

Expanding Symbols

A special symbol, usually during a Free Spins round, that is chosen to expand and cover the entire reel it lands on, paying on non-adjacent reels.

This is the legendary mechanic at the heart of every "Book of..." slot, and it's one of the most powerful features in iGaming. At the start of a Free Spins round, a regular symbol is chosen at random. During the spins, whenever this special symbol lands, it expands vertically to fill the entire reel. Crucially, these expanded symbols pay out like Scatters – they don't need to be on adjacent reels to form a win. Landing one on each of the five reels results in a "full screen" win, which is usually the game's Jackpot prize.

Real-World Examples

- Book of Dead (Play'n GO) - The undisputed king of the expanding symbol mechanic
- Legacy of Dead (Play'n GO)
- Book of Ra (Novomatic)

FAQs

What's the best symbol to get chosen?<br>You want one of the high-paying picture symbols. Getting the top character symbol chosen is the dream, as a full screen of him will pay the game's maximum prize.

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