Expanding wild
An expanding wild is a wild symbol that grows after it lands, usually stretching to cover its whole reel so that every position on that reel substitutes for paying symbols. The effect normally lasts for the spin on which it appears, though some games add a re-spin with the wild reel held. Which reels it can land on, and whether it expands every time or only when it completes a win, is set by each game’s paytable rather than by any shared standard.
How an expanding wild plays out on the reels
The best-known case is NetEnt’s Starburst, where the wild appears only on reels two, three and four. When one lands it fills its reel, locks in place and the other reels re-spin; each new wild repeats the trick, up to three wild reels and three re-spins.
Because a full reel crosses every payline, one expanded wild on a ten-line game can complete several lines at once.
That does not make the game more generous. The expansion is already priced into the published RTP, so the feature changes how wins are distributed across a session, not how much the game returns over the long run.
Wild features often mistaken for expanding wilds
Several wild behaviours sit close together in paytables, and the names are not used consistently between studios. The descriptions below reflect common usage across published game rules.
| Feature | What it does | Key difference |
|---|---|---|
| Expanding wild | Grows to cover its reel | Usually lasts one spin |
| Sticky wild | Stays put for later spins | Does not grow |
| Walking wild | Moves one reel each re-spin | Changes position, not size |
| Stacked wild | Lands already filling several positions | Arrives tall, never grows |
| Expanding symbol | Chosen symbol fills reels in free spins | Often not a wild, as in Book of Dead |
Reading the rules before you spin
What I check first is the game’s information screen, since it states which reels can carry the wild and whether expansion is automatic.
Some titles keep expanding wilds for the free spins round only, while others let them appear in the base game, and a few expand only when the extra positions would form a win. None of this alters the randomness of each spin: a reel that turned wild a moment ago makes the next one no more likely.
