Expanding Wild Slots
An expanding wild stretches over its reel or row and substitutes from every covered cell, with the trigger and timing stated in the rules.
How expanding wilds work
An expanding wild lands as a single symbol and stretches to cover a larger area, most often its whole reel. Every covered cell then substitutes at once, so one landing can complete several wins across the grid. Vertical expansion over a reel is the standard form, and some games expand across a row or in both directions instead.
The timing is the first rule to read. Some games expand the wild on landing regardless of the result, whilst others expand only where the stretch would join a win. The two designs pay very differently from the same landing, and the paytable states which one the game uses.
The trigger is the second rule. Expansion can be the symbol’s standard behaviour, a chance event or a behaviour reserved for a feature. Games frequently keep the expanding form inside Free Spins whilst the base game carries ordinary Wild Symbols, and the rules mark the difference.
Expansion combines naturally with holding behaviour. A wild that expands and then stays for following spins joins the territory of Sticky Wilds, and games that combine the two state the held duration separately from the expansion rule.
The feature is fully described by three stated facts, namely the direction of the stretch, the moment it happens and the trigger it needs. A paytable that prints all three has said everything the player needs, and one that prints an expanding wild with no timing rule has said very little.