Jurassic Express (2019–2022)

On May 25, 2019, Matelson debuted for All Elite Wrestling (AEW) at Double or Nothing as a part of the pre-show Casino Battle Royale. He lasted until the final three, before being eliminated by Adam Page.^[16] Three days later it was revealed that he had signed with the company full-time as Luchasaurus.^[17] He would then go on to form a tag team with Jungle Boy as he managed him at Fyter Fest and teamed up with him at Fight for the Fallen in a Triple Threat tag team match involving The Dark Order and Angelico and Jack Evans in a losing effort. At All Out, Luchasaurus alongside Jungle Boy and Marko Stunt would debut as the stable "Jurassic Express". Luchasaurus also sporadically competed as a singles competitor, most notably participating in the Casino Ladder match at Double or Nothing on May 23, 2020.

Jurassic Express received title shots for the AEW World Tag Team Championship against Adam Page and Kenny Omega on the August 12 episode of Dynamite, and The Young Bucks on the August 18, 2021 episode of Dynamite, but failed to win the title on both occasions. Following that, Jurassic Express participated in a tournament to determine the #1 contenders for the World Tag Team Championship, defeating Private Party in the opening round before losing to Lucha Brothers in the final. On the January 5, 2022 episode of Dynamite, the Jurassic Express defeated the Lucha Brothers to win their first World Tag Team Championship.^[18]

At the Revolution event on March 6, Jurassic Express successfully defended the championship against The Young Bucks and reDRagon (Bobby Fish and Kyle O'Reilly) in a three-way tag team match.^[19] At Double or Nothing on May 29, they retained the championship in a three-way tag match against Team Taz (Ricky Starks and Powerhouse Hobbs) and Swerve In Our Glory (Keith Lee and Swerve Strickland).^[20] After Jungle Boy and Luchasaurus lost the titles to The Young Bucks in a ladder match at Road Rager, Cage turned on Jungle Boy, with Luchasaurus also turning heel when he joined Cage.^[21] At the start of his alliance with Cage, Luchasaurus was presented as a “monster heel” and started squashing multiple opponents within minutes, all at Cage’s direction.

TNT Champion and The Patriarchy (2022–present)

At Fyter Fest week two, Luchasaurus turned on Christian Cage to realign with Jungle Boy, however, this was also a short-lived reunion. At the All Out event, Luchasaurus cemented himself as a heel by attacking Jungle Boy once again and solidifying his alliance with Cage. As a result, Luchasaurus began feuding with "Jungle Boy" Jack Perry, defeating him in a match on the October 12 episode of Dynamite. However, Luchasaurus lost to Perry in a steel cage match at Full Gear to end the rivalry. Following the loss, Luchasaurus went on a hiatus. He returned to AEW in April and reunited with Cage.

On the June 17, 2023 premiere episode of Collision, Luchasaurus defeated Wardlow to win the TNT Championship.^[22] Luchasaurus held the title for three months, retaining against Shawn Spears at Battle of the Belts VII, Brock Anderson on the August 12 episode of Collision and Darby Allin at All Out. Luchasaurus would later lose the title to Cage in a three-way match that also involved Allin on the September 23 episode of Collision.^[23] At WrestleDream, Cage defeated Allin in a two out of three falls match to retain the championship. After the match, Cage, Luchasaurus, and Nick Wayne (who turned against Allin) assaulted Allin and Sting; they were interrupted by the debuting Adam Copeland, who ran out to confront Cage and save Allin.^[24] Cage's faction was later called The Patriarchy.^[25] At Full Gear, The Patriarchy lost to Copeland, Sting, and Allin in a six-man tag team match with Luchasaurus taking the pin.^[26] On the November 22 episode of Dynamite, Cage renamed Luchasaurus as Killswitch (named after Cage's finishing move) and dubbed Killswitch as his "finisher".^[27] At Worlds End, Killswitch won a 20-man battle royale for a future TNT Championship title match. Later that night, Cage lost the TNT Championship to Copeland in a no disqualification match. As Killswitch was about to sign off his title match contract on Copeland, Cage demanded Killswitch to hand over the contract and Killswitch relented. Cage then defeated Copeland to regain the TNT Championship.^[28][29]