Wilds are the most common — and most misunderstood — bonus mechanic in slots. Here is every kind you will see.
A Wild symbol is a symbol on the reels that substitutes for other symbols to help you complete a winning line. Most wilds substitute for every paying symbol except scatters and bonuses.
Think of a wild as a joker in a deck of cards. It fills in for whatever you need to make a paying combination.
The classic. Land it on a payline and it pretends to be whichever symbol completes the longest possible win. If your reels show cherry — cherry — WILD, you collect the three-cherries payout. Some standard wilds also pay on their own (the wild has its own value on the paytable).
When a wild lands, it expands to cover the entire reel (top to bottom). Suddenly you have 3, 4 or 5 wild positions instead of one — massively increasing the chance of multi-line wins.
Book of Ra-style slots, fruit-themed video slots, and any "high-volatility" slot where the developer wants rare-but-massive payouts.
Stacked wilds appear in clumps of 2–5 already attached vertically. Land a stack on the first reel, get a stack to fall on the third reel, and you have a screen full of wilds — often resulting in five-of-a-kind wins on every payline.
Once a sticky wild lands, it stays in place for the next spin (or several spins, depending on the slot). They are almost always exclusive to bonus rounds because they are very powerful — stickies plus respins can chain together into mega-wins.
A wild that moves one reel position each spin. It "walks" across the reel grid over consecutive spins until it walks off the edge, often triggering a re-spin for every step. Net effect: one wild lands, you get 4–5 spins of bonus value.
A wild that not only substitutes but also multiplies the resulting win — commonly 2x, 3x, 5x, or even 10x. Stack two multiplier wilds on the same line and the multipliers multiply each other: a 2x and a 3x become a 6x win. Hunt for these stacked.
Common in cascading-reels slots. After a winning combination clears, new symbols fall in — sometimes a wild is placed where the winning symbols used to be, helping the next cascade hit too.
A scatter is a symbol that pays regardless of where it lands on the reels (no need to be on a payline). Scatters usually trigger bonus rounds, free spins, or pick-bonus games. Wilds substitute; scatters trigger. Some slots have wild-scatters that do both — rare, but they exist.