CroByss was a Pokémon Trading Card Gamedeck archetype that saw success toward the end of the 2003-2004 season, after the release of EX Hidden Legends in June 2004. Its name is a blend of Crobat and Gorebyss, the deck's two main attackers. CroByss was one of several popular deck archetypes of the era to include Gorebyss, the others being MetaByss; Jumpluff/Gorebyss; and a number of decks focusing on Stage 1 attackers. The deck took first place at the South Stadium Challenge in Arlington, Texas in July, 2004, and had at least one Top 32 finish at the 2004 World Championships. CroByss functions as a disruptive deck, using a combination of Crobat and Gorebyss' attacks to alternately damage and stall the opponent while restricting his or her hand size with Desert Shaman.
The synergy between Crobat and Gorebyss was admittedly limited, but they complimented each other in that they were non-ex Pokémon that were capable of attacking for only one or two Energy. Crobat's Flutter Trick attack combined well with the disruption caused by Desert Shaman. Desert Shaman could also make it difficult for an opponent to find the resources necessary to get a Poisoned Pokémon out of the active position, increasing the effectiveness of Crobat's second attack, Triple Poison. Gorebyss provided another inexpensive attacker, and one that was particularly effective against Blaziken ex-based decks (widely considered to be the strongest attacker of the era).
Crobat - Crobat was one of the deck's two primary attackers, capable of attacking for only one or two Energy.
Gorebyss - Gorebyss served as the deck's other primary attacker, and served as a hard counter to Blaziken ex.
Dunsparce - Dunsparce was the deck's ideal starter Pokémon. With its Strike and Run attack, Dunsparce could instantly give the player a strong setup; most decks of the time relied on Dunsparce early in the game.
Desert Shaman - Desert Shaman provided a means for CroByss to downsize the opponent's hand, which was particularly effective in combination with either of Crobat's attacks. Because CroByss was a quick deck that often set up before its opponent, a Desert Shaman early in the game was typically much more disastrous for an opponent than for the Crobyss player.
Double Rainbow Energy - Double Rainbow Energy provided a way to power up either Crobat's Triple Poison or Gorebyss's Mystic Water in only one turn.
The deck list appearing below is not official; it is meant to represent an average build of the archetype, not specifically constructed for any regional metagame. Being that this is merely an archetype, a player may wish to change any part of this deck when building his or her own version. The list shown assumes an Expedition through EX Hidden Legends format. Potential later additions may be listed in the Possible tech cards section.
Igglybuff - Igglybuff served a similar purpose, but with the option of retrieving an Energy card. Given CroByss's reliance on a variety of different Energy types, this could prove useful.
Ditto - Ditto served a number of purposes. Its Prismatic BodyPoké-BODY allowed Water Energy and Grass Energy to count as Psychic Energy when applied to the damage output of Gorebyss's Mystic Water attack. Ditto also served as a powerful attacker in some matchups, hitting Rayquaza ex (one of the most popular attackers of the era) for Weakness and being able to effectively copy the attack of opposing Gorebyss.
Ancient Tomb - In areas where the metagame included many Lightning-type and/or Psychic-type Pokémon, a CroByss player may want to include Ancient Tomb to negate the weaknesses of Gorebyss and Crobat, respectively.