Wild symbols are one of a slots player’s best friends. When they drop onto the reels they can create winning paylines from losing ones, and in today’s online slot machines they are responsible for a lot of action.

They’ve been around since the birth of mechanical slot machines, but just as slots have evolved with the advent of high-quality software and graphics, so wild symbols have evolved, and game developers are using them in increasingly innovative ways. There are now such wilds as expanding wilds, sticky wilds, shifting wilds, cascading wilds, and stacked wilds, all of which perform in different ways to add excitement and enhance gameplay.

What are Wild Symbols?

Wild symbols are like the joker in a pack of cards. The joker can be used as a substitute for any other card to make a winning hand; and with slots, the wild symbol is used as a substitute for any other symbol to create a winning payline. There are some basic rules to wild symbols – that they can’t replace a scatter symbol, and usually can’t replace free spin or bonus symbols – but otherwise, they can only serve to generate extra wins.

On the traditional three-reel slots with just one payline, the wild symbol was a basic affair. If you landed two matching symbols and a wild symbol you would be paid as if you had landed three matching symbols. Online games have become much more sophisticated now that they are powered by software, and wilds have really come into their own. Developers are using animations, video footage and sound effects to signify wils, and with five or seven reels and multiple paylines, there are plenty of wins to be generated when a wild symbol hits the reels.

How do Stacked Wilds Work?

Stacked wilds have taken on various forms as developers try different animations, but the general rule is that stacked wilds appear as several symbols stacked on top of each other, which cover part or all of a reel. This can lead to multiple winning paylines as the wild covers more than one reel position. They are usually seen in stacks of 2, 3, 4, or 5 wild symbols, but some use animations to cover the reels instead, in a similar way to expanding wilds.

Some games have stacked wilds on every reel but some only allow them on certain game reels, while others appear only in free spin bonus rounds. Combined with free spins and multipliers, stacked wilds can lead to some huge wins when you come across them in bonus games.

IGT’s Western Belles slot is a great example of an online slot which uses stacked wilds. When you play the game for the maximum 40 lines, one reel is guaranteed to be fully wild on every spin, while the slot also features stacked wild symbols which can land on any of the other reels at any time. This is a great addition to the base game, as it creates plenty of action on every spin.

Variations on the Wild

Stacked wilds can lead to great wins, but they are just one of the many different types of wilds found in today’s online slots. We’ve already mentioned expanding wilds, which are similar to stacked wilds except that they usually always cover the entire reel, where stacked wilds sometimes only cover part of it.

Sticky wilds are also popular, and they stay on the reels for several spins, generating more wins as each set of symbols lands around it. Sticky wilds are often seen in free spin bonus rounds, where they can really help to rack up the winnings. Shifting wilds work in the same way by staying on the reels for a period of spins, but they move around the game board, taking up a new position on the reels for each spin, until they eventually shift away from the reels and off the screen.

You can read about the different types of wild in detail in our guides, but if you want to get playing, check out our guide to free online slots where you can try out a range of games for free. If you’re keen to progress straight to real money slots, you’ll find everything you need to know about online casinos on our review pages.