Colossal symbols in slots

What colossal symbols in slots are

A colossal symbol is a single picture that spans several reels and rows. Instead of nine separate cells each landing their own symbol, a 3×3 colossal block covers all nine with one image. For the purpose of paying wins, most games treat every cell under the block as an ordinary copy of that symbol.

Developers also call them giant, jumbo, big or mega symbols, and the naming is not standardised. Whatever the label, the job is the same: put a lot of matching symbols on screen in one go. They sit among the wider set of slot machine features that change what the reels show after the RNG has chosen the result.

How colossal symbols land on the reels

A reel strip on a video slot is a long list of symbols, and the random number generator picks a stopping point on each. To show a block that spans three reels, the game has to treat those reels as linked for that spin. Studios do this in a few ways.

1. The RNG picks a stop for each reel, or for a linked group of reels, before the animation begins.
2. If the stop on the linked group falls on a colossal segment, the game draws the block across those reels.
3. The block can be fully visible or cut off, with only its top or bottom rows on screen.
4. Every visible cell of the block is filled with the block’s symbol for win evaluation.
5. Wins are counted across lines or ways, then any multipliers are applied.

Partial landings are normal. If a 3×3 block stops one row low, you see only its top two rows, and only those six cells count. The reel strips decide how often a block appears and how often it appears in full; neither can be read from the screen.

Worked example: a 3×3 colossal block on a 243-ways slot

Take a 5×3 slot that pays 243 ways. A colossal 3×3 lion lands across reels 2, 3 and 4, so all nine middle cells show a lion. Now count matches from the left.

If four lions pay 2p per way at your stake, one lion on reel 1 with the block gives 27 × 2p = 54p. Without the block, the same spin might have paid one or two ways. The block does nothing at all unless the first reel cooperates, which is why colossal features often come with a wild or a forced match on reel 1.

Colossal symbols on payline slots

On payline slots, a full 3×3 block on reels 2 to 4 covers every row on those reels, so every line passes through it. Whether a line pays then depends only on reel 1 (and reel 5 for five of a kind). On a 20-line game, a matching symbol in the top row of reel 1 completes every line that starts in that row; a match in each row of reel 1 completes all 20.

This is what makes blocks feel dramatic: a single landing can light up most of the lines at once. The total paid, though, is still the sum of ordinary line wins from the paytable.

Colossal reels: the two-grid format

‘Colossal reels’ is a separate design. The screen shows a standard reel set beside a much taller one, and the two are linked so that stacks on the small set carry across to the large set. It is closely associated with WMS, now one of the Light & Wonder brands alongside Barcrest.

Reels of Gold, from Barcrest, is the colossal-reels game in our database: its spec lists a 5×4 reel set plus 5×12 colossal reels, up to 100 paylines, an RTP of up to 96% that varies with stake, and a 2016 release. Because the RTP varies with stake, check the help screen at the stake you plan to use.

Slots with colossal symbols in our database

Starburst Galaxy shows how a colossal wild changes a familiar game. The original Starburst uses single expanding wilds; the 2024 follow-up, according to OLBG’s Starburst Galaxy listing (opens in a new tab), places a 3×3 Starburst wild on an expanded 7×7 grid in its Galaxy Star feature, with a 25,000× max win.

A colossal wild is the strongest form of the idea, because it matches every symbol at once. Reactoonz uses a 3×3 Gargantoon wild on a cluster grid, which our mega symbols page covers in more depth.

What colossal symbols do to volatility and cost

A block that fills nine cells creates outsized wins when it lines up, and nothing when it does not. To fit that into a fixed RTP, the game pays less on ordinary spins. That pushes volatility up: more quiet spins, a few sharp peaks.

If a casino runs the 94% version, the long-run cost of 100 spins at 20p rises from about 80p to about £1.20, half as much again. Always check which RTP is shown in the game.

Colossal symbols versus stacked and expanding symbols

Three features can fill a reel with one symbol, and they are easy to confuse. A stacked symbol is a run of the same symbol in consecutive positions on one reel strip; it fills one reel vertically. An expanding symbol starts as one cell and grows to fill its reel after landing. A colossal symbol spans several reels at once, in a block.

Fruit machines, myths and colossal symbols

Traditional fruit machines use physical or fixed-size reels, so there is no true colossal equivalent; the closest effect is a heavily stacked symbol. On Category C pub machines the stake is capped at £1 and the top prize at £100, per the Gambling Commission’s machine categories (opens in a new tab), so a screen full of one symbol is still limited by the category.

• Myth: a block that landed one row short means a full block is coming. Fact: each spin is independent, and partial blocks are part of the design.
• Myth: colossal features make a slot ‘loose’. Fact: the RTP is fixed; blocks redistribute it into bigger, rarer wins. There are no loose or tight machines.
• Myth: you can time a spin to catch the block. Fact: the RNG decides the result before the reels move.

UK rules that apply to colossal symbol slots

Every online slot offered in Great Britain, colossal features included, has run without autoplay, turbo or slam-stop since 31 October 2021, with each spin lasting at least 2.5 seconds. Stakes are capped at £5 per spin for players aged 25 and over and £2 for 18–24s, as set out in the Commission’s online slots stake limit guidance (opens in a new tab). Bonus buy is not offered on UK versions. For the full picture, see our slot game design rules page.

Where to play colossal symbol slots in the UK

Our partner offers are not tied to a colossal-symbol game. Coral gives 100 free spins at 10p each on selected games when you deposit and bet £10 on slots; Ladbrokes gives up to 500 free spins at 10p, 50 a day for 10 days, after you play £10 on slots; PlayOJO gives 80 free spins at 10p on Big Bass Bonanza with a first deposit of at least £10, and winnings carry no wagering. 18+, new customers only, terms apply.

For Starburst Galaxy, Reels of Gold or Reactoonz, search the casino’s lobby, as availability changes. Compare our partners on the casinos page. If you want to block gambling sites for a while, GAMSTOP (opens in a new tab) offers free self-exclusion from all UK-licensed online casinos.

18+. Gambling should be entertainment that costs money, not a way to make it. Decide a budget before you play: plan a slot budget. Free, confidential help: National Gambling Helpline 0808 8020 133.