Online slot games are the most popular of all casino games. Players are required to obtain a combination of like symbols in enabled paylines in order to receive payouts. This process has been made more interesting by the introduction of a wild symbol. In the slot games of some online gaming software providers this symbol is known as the substitute symbol. In its simplest form the wild symbol merely substitutes for any other symbol so as to make a winning combination as described in the pay table. However, over the years the wild symbol has become more functional and more exciting.

Online slot games depict themes. The wild symbol plays a pivotal role in the theme. For example in the slot game Thunderstruck, Thor is the wild symbol. In the recently released Mayan Queen, the Mayan Queen is the wild symbol. Animation of symbols has become an integral part of online slot games. And it is the wild symbols that usually have the best animation.

In many online slot games the wild symbol acts as a multiplier. This means that if the winning combination is made with the help of a wild symbol than the player gets a specified multiple of the payout given in the pay table. Very often wild symbols are used to trigger the bonus rounds. When a specified number of wild symbols appear on the reels then the players get to play a bonus round in which they are entitled to additional payouts but need not make additional wagers.

Usually at most one wild symbol appears on a reel. However in some slot games there can be more than one wild symbol appearing on a reel. Such wild symbols are known as stacked wilds. Sometimes stacked wilds are restricted to the free spins round, and in other games they appear in normal spins as well. Summer Holiday is a popular slot game with four rows and stacked wilds appearing in all of them. In the stacked wilds each wild symbol retains its identity. However in some slot games the wild symbols appearing on the same reel merge together a form a different visual. Such wild symbols are known as expanding wilds. These symbols are usually connected with people. The portraits shown in the normal wild symbols give way to a life size figure that covers the entire reel. Samba Nights is one slot game that has expanding wilds. The full size animated figure of the Samba dancer is a visual delight. It must be added that apart from the visual appeal stacked wilds and expanding wilds offer additional winning chances and are therefore also very popular.

There are slot games in which under certain circumstances additional wild symbols are created. In some games designated bonus symbols function as wild symbols in the free spins bonus round. However, the more exciting option of creating wild symbols is what is known as exploding wilds. When the reel stops, on occasions, other symbols are randomly converted to wild symbols. Usually this happens with some form of sound effect and hence the term “exploding wilds”. The best example of this is the slot game Call of Duty 4. In this slot game there is actually an explosion created by some kind of visual detonator and a number of wild symbols are created.

Online slots have become very competitive and the software providers are adding more and more features to their games. As slot games continue to evolve the wild symbols will also take on many new functions and formats.