Trapball is an elcor sport, famed for the length of time necessary to complete a match (even by elcor standards), and the incomprehensibility of its rules.
The sport, native to Dekuuna, is played on an open-air ground between two teams of eighty-four players. The attacking team is represented by two, or occasionally four (the "extra game" rule), players, who take it in turns to hold the "twig", a fashioned stone-wood bat. The defending team takes the field in its entirety, with one player - the roller - proceeding to gently roll the "hedron" (a ball, although under certain conditions it may be replaced with a solid of a number of sides to be determined by a sub-umpire) towards the twig-holder - the nudger - who will nudge it away and walk from one end of the designated nudgers' playing area to the other, in opposition to his partner, scoring "ambles" (the length of which varies from five to seventy minutes, depending on strategic considerations) while the defending team moves to secure the hedron.
A number of special rules complicate matters, including the Thirty-Seven Degree rule (affecting the position in which the nudger is permitted to hold the twig with regard to his off-side limb and a rock placed part-way along the pitch), the Visor Trick Caveat (which resets the amble count to the square root of the current amble-per-innings rate), and most notoriously the Volworth-Metis Method, a means of determining the result of a match interrupted by meteorological conditions, which involves quantum algorithms.
Trapball does not have a large following beyond elcor, with most aliens finding the rules too labyrinthine to comprehend and the game itself - which can last anywhere from one month, in the newly-introduced "rapid result" format, to several years for a full test match series - rather long. Some asari have been known to take the time to learn the basics of the rules in order to follow it; cross-species researchers have noted with interest their inability to locate any salarian fans of the game, theorising that it may be fundamentally incompatible with the salarian psyche.
Trapball should not be confused with the similarly-named krogan pastime "trap-ball", the only common feature being that an object is thrown by one player at another, though with considerably more force.
"The Cinders" is a traditional trapball test series, played once per generation on Dekuuna, widely considered the most significant recurring contest in the sport's history. Rivalry between the two teams - Imperials and Colonials - run hot, with a history of sedate confrontations and terse half-hour exchanges of angry words between rolls, and similar polarisation among fans. During the Cinders series of 2168 (ongoing) a controversy flared when star strike roller Yefilo was repeatedly ruled by sub-umpire Pradok to have used an illegal rolling action over the course of a two-week rolling spell, a ruling which prevented the dismissal of Colonial stalwart Gherom, who at the commencement of the controversy had been nudging unopposed for fifteen days. The sport's governing body, the TCC, conducted VI-assisted recreations of Yefilo's rolling action, but were unable to reach agreement on the validity of Pradok's ruling. An emergency session of the Counts of Trapball eventually elected to replay the previous three months' play, in the interest of fairness.
Previous series have seen equally divisive incidents. During the notorious "bio-line" series, it was alleged that the entire Colonial team had used military-grade stealth rigs to infiltrate the playing field by night and urinate on the pitch to affect the passage of the hedron during the following day's play.
Trapball is, of course, cricket, only slower and more confusing to outsiders, as possibly only the elcor could achieve.