Sandbagging

Sandbagging, sometimes formally referred to as "intentional underperformance", is the act of playing poorly on purpose. Originating from Billiards slang, referring to the concealment of one's ability to play, sandbagging in the Super Smash Bros. series generally consists of players using characters that are not their main characters, selecting stages that normally counter their character, or playing below their proven capabilities, amongst other actions. Sandbagging can occur at any level of play, and even at top-level tournaments players have sandbagged on occasion, with some smashers, such as and, being well-known  for their frequent sandbagging.

Sandbagging is sometimes done in friendlies in order to prevent spectators or opponents from learning their playstyle with their mains. If the skill difference between two players is particularly significant, higher-skilled players can also potentially sandbag. The reasoning for sandbagging can vary, though in both cases, it can be used by players to relax in lower-stress matches, as well as potentially allow for an opportunity to work on other characters; in the case of differences in skill, the sandbagging player can also give their opponent a "fairer" match.

Sandbagging, however, can be seen as a sign of disrespect when done in serious settings, as it is seen as the player not treating their opponent as an equal nor as a threat, as well as depriving their opponent of a pure competitive match. Due to compromising a tournament's competitive integrity and disrupting the natural progress of the tournament bracket should a sandbagging player lose against a lower level opponent, it is not uncommon for tournaments to have a rule forbidding intentionally underperforming at the threat of being disqualified from the tournament altogether and possibly banned from future tournaments. This is a controversial ruling though, as it is not always clear if a player is sandbagging, thus making it difficult to enforce. Additionally, there is the argument that it is the right of the player to perform however and use whatever character they want. There is also the argument that a player may simply enjoy playing as the character even if they do not normally play them seriously.

Notable incidents of sandbagging

 * went through a period where he adopted the persona of "", and used at several tournaments; the most well-known of these instances was Apex 2010, where he placed 25th in Melee singles instead of his usual top 4 placing.
 * American Smash 64 player Isai is infamous for his frequent sandbagging at tournaments for the game, often by refusing to use his main in high-stakes matches or by using low or bottom tiered characters throughout a tournament.
 * At Apex 2012, Isai only used the bottom-tiered en route to a second place finish to . In an exhibition match against  in Melee at the same tournament, Isai used his Melee main,, but played in an obvious sandbagging manner against Captain Jack.
 * At the Smash 64 tournament in Apex 2013, Isai again sandbagged with his character choice, this time using, despite the crowd yelling for him to use several times. He placed second again, this time defeating SuperBoomFan, but losing to  in winners' and grand finals.
 * At the Smash 64 tournament in Apex 2014, Isai once again sandbagged by exclusively using the mid-tiered . Unlike Apex 2012 and 2013, however, Isai placed first in singles without losing a single set, with placing second below Isai.
 * Canadian Fox main,, incited controversy at Revival of Melee 5 by refusing to play his main against in the grand finals, claiming to be tired, likely as a result of the controversy that had already occurred.
 * Ford would then cause similar controversy in NEC 13 by again sandbagging against Mew2King in winners' bracket.
 * Mew2King regularly sandbags in Melee, mostly in locals, smaller tournaments, or pools against opponents he does not deem to be competent enough, or if he is already guaranteed first seed in a given pool. This is done mostly to give himself more of a challenge and entertain spectators, and most of his opponents have reportedly not minded this habit. Mew2King's sandbagging generally consists of using bottom-tiered characters like, , , and ; if he is using , he may also opt to transform into  at the end of a clearly uphill match. Mew2King also allows the opponent to choose any stage they want via the Gentleman's Rule, and may even allow players to turn items on or use the game's various Special modes, resulting in unusual tournament matches. Notable examples include:
 * Winning against in a biweekly using Pichu.
 * Defeating a low-leveled player with his own Bowser and Mewtwo.
 * Choosing Mewtwo and Roy to fight against in Grand Finals after winning the first two matches with his usual Sheik and Fox.
 * Choosing and  against a low-leveled Link player, and allowing him to strike to Venom and counterpick Onett.
 * In Grand Finals, fighting his opponent in Tiny Melee with Mewtwo on Fourside, then Lightning Melee, then with Poké Balls on.
 * A controversial case of sandbagging, however, occurred at the Brawl tournament at GENESIS 2; Mew2King was red carded by the Unity Ruleset Committee for using and  in a losing effort against  in pools, after defeating everyone else in his pool with his usual.