Spectator Mode

Spectator Mode (shortened to Spectate) is an online mode in Super Smash Bros. Brawl, Super Smash Bros. 4, and Super Smash Bros. Ultimate, allowing players to remotely view recent replays of online battles between other players and bet on their outcomes (except in Ultimate). The matches to be viewed are selected at random from recently played matches in the public online modes (With Anyone in Brawl, For Fun and For Glory in Smash 4, and Quickplay in Ultimate).

In addition to recent replay viewing in the Spectate menu, Ultimate also features live match spectating in Battle Arenas.

In Super Smash Bros. Brawl
Spectator Mode was available within the With Anyone sub-menu. When viewing a match, only the characters used and stage was shown, with the names being omitted.

Before the match started, players could optionally bet up to 100 on possible winning players or teams. Once the match starts, the coins were immediately deducted from the players, so no attempts could be made to retrieve them if the bet was lost. Players would receive stickers regardless of if they won or lost the bet. However, should their bet be correct, the player would win the "Jackpot", which was their original bet multiplied by a multiplier contingent on the number of players in the match:

Assuming the player had no information about the match and so bets at random, the spectator would statistically lose coins in the long run. For very small bets however, the value was rounded up, giving a neutral payout overall.

Occasionally, spectators were offered a "Bonus Chance". If the bet was correct, the spectator would also win one of the following:
 * Small sticker bundle, consisting of 10 stickers.
 * Medium sticker bundle, consisting of 20 stickers.
 * Large sticker bundle, consisting of around 45 stickers.
 * A relatively rare trophy.
 * A CD, provided there were still random songs left to unlock.
 * Doubled winnings from the bet.
 * Tripled winnings from the bet, with a maximum of 999 coins.

As betting was done at a loss in the long run, betters would have had to apply matchup knowledge to their betting strategies and take advantage of bonus chances in order to gain coins in the long run.

In Super Smash Bros. 4
Spectator Mode returns in Super Smash Bros. 4. The Nintendo Network ID of the players is displayed, alongside the character used, and their win percentage. A multiplier between 2 and 10 is calculated (displayed rounded to 1 decimal point) based on this win percentage (or a combination of two in Team Battles). The multiplier is lower for those with higher win percentages and higher for those with lower win percentages. Prior to the match starting, spectators may optionally bet up to 100 (shortened to "G") on possible winning players or teams. Should the chosen player win the bet, they will receive the Jackpot, which is their wager multiplied by the winning combatant's multiplier. Afterwards, the player is given the option to go for a "Winning Streak" - betting with winnings from the previous game instead. This results in a much larger potential for payouts. However, after the third consecutive win, the winnings are automatically paid out (which may result in the unlikely, but achievable 100,000G theoretical cap).

In four-player matches, should the chosen character come second, called a "Near-Win", then the spectator will be rewarded with an automatic and much smaller "Nice!" payout.

Bonus Chances also return, awarding extra gold, trophies, and other rewards, though only in the case of a "Jackpot" outcome.

As a result of new bet multipliers and "Near-Win" payouts, betting is much more profitable in SSB4 compared to Brawl, due to an almost guaranteed long-term payout, assuming a good betting strategy is used.

In Super Smash Bros. Ultimate
Spectator Mode returns in Super Smash Bros. Ultimate. Unlike in previous games, players no longer bet coins on players or teams. Instead, as of version, players can "Cheer"/"Support" to win Prediction Points which can be used in an exclusive shop and spent on Spirits, snacks, Spirit Board items, Classic Mode Tickets, Gold, and Spirit Points.

For each accurate prediction, the player earns Prediction Points. The longer the streak of correct guesses, the more Prediction Points each subsequent prediction will earn. An exploit exists where entering the prediction points shop and immediately exiting loads a new match but retains a player's streak, which can be used to avoid matches the player is not confident in making a prediction and prevents the player from losing their streak.

Trivia

 * In the NTSC version of Brawl, if a match was a free-for-all, the top-right corner would incorrectly read "Quick Brawl", as opposed to the correct term, "Basic Brawl". This error was later fixed for the PAL regions.