Wild symbols have long been a favorite among slots fans, as there’s never a time when seeing one on the reels isn’t a positive for you. They help make winning combinations all over the place, after all, and many also come with multipliers or big prizes in top of their other special abilities. So how can you improve on this classic feature?

One way in which some online slot developers have tried to breathe new life into this concept is with the addition of random wilds. These substitute symbols aren’t just icons that can show up on a lucky spin. Instead, they show up when you least expect them as part of completely unplanned special features, adding a new level of excitement to each and every spin.

Random wilds can work in different ways depending on just what machine you happen to be playing. However, they do have a few common attributes that distinguish them from other special features.

First, they tend to act like your standard wild symbols. This means that they can fill in for any normal symbol, completing winning paylines wherever they can. Some might also come with multipliers; when they do, this means that any winnings you earn using those symbols will be increased by that amount.

Of course, the difference here is that these symbols will appear without warning. Typically, we’re referring to symbols that appear after a spin is completed. This can sometimes appear during normal play, but may also be part of free spins games or other bonus rounds.

How these bonuses impact gameplay can vary based on the game you’re playing. Sometimes, one or more symbol locations will turn into wilds, awarding new prizes as a result. In other games, entire reels might turn wild for a free spin. In any case, these changes can happen on any spin, making them truly surprising. However, wins are not guaranteed and it can be frustrating seeing the wilds line up on the wrong symbols with no winning lines.

Many top online slot machines have random wilds in some form or another. We’ll take a look at just a couple of these games to see how they implement this idea in different ways, each of which can create a sudden windfall for lucky players.

First off is?Microgaming’s Immortal Romance. This teen vampire-themed game has become popular for a number of different reasons: its 243 ways format, the story features that lay out a Twilight-like world for players, and the original score of pop/alternative music that plays throughout the game. But the very best feature in the game might be Wild Desire.

This bonus round can be triggered at any time at the start of a spin. When it takes hold, anywhere from one to five reels can turn entirely wild before the other reels fall into place. That means it’s possible for every space on the screen to turn wild, potentially winning players over 3.6 million coins on a single spin.

A similar feature can be found on The Dark Knight, another game from Microgaming. This game is punctuated by the two archrivals from the movie it is based on: Batman and the Joker. Both characters can appear on screen at the end of any spin, changing things to the player’s advantage.

While the Joker will simply give the player a number of credits, however, Batman will throw wilds on to the screen. Symbols on up to three different reels can turn wild each time he appears, which can easily turn a spin that was a complete bust into a huge win.

Batman isn't the only?comic book slot game to feature random wilds. They also appear in the?Marvel slots by Playtech. In the Playtech games they appear during the free spins bonus round. Each spin results in wilds appearing randomly on the reels which can result in more bigger wins.

The biggest advantage to random wilds is the fact that they bring a ton of surprise value to games where they appear. When a bonus feature could appear for you at any time, you’ll be engaged in every spin, meaning that game never feels boring. It’s something like a more mild form of a progressive jackpot bonus that can be triggered at any time – you may not win millions, but the added substitutes could still prove valuable when you least expect them.

That said, overusing this idea can actually be a downside for an online slot machine. The problem is that these bonuses are truly random, which means that an unlucky player can go a long time without triggering them. That’s not a big deal if the game is interesting outside of the special bonus – the two games we mentioned above are great examples of machines that use this concept without relying on it too much. On the other hand, if random wilds are the main bonus round, players could easily get bored before they ever manage to see it in action.