Thunder is the stage name for the horse who is the official live animal mascot for the Denver Broncos football team.

Thunder shares mascot duties with Miles, a human who wears a horse head mask atop a Broncos uniform.

Three purebred Arabians have held this role since 1993, all gray horses whose coats lightened with age until they turned completely white.

Thunder III also made appearances in Times Square and on television morning news shows in New York City as part of the pre-game promotion for Super Bowl XLVIII.

He retired from mascot duties in early 2014 but appeared in the 2016 Super Bowl 50 victory parade in downtown Denver following the Broncos win over the Carolina Panthers.

Thunder IV, registered as Phantom JD, is the current mascot and began making appearances in the 2021 season.

The original "Thunder", JB Kobask, was loaned to the Denver Broncos by Sharon Magness-Blake of Magness Arabians after she received a phone call from team officials asking if she had a "white" horse.

[2] Magness said, "Thunder is friendly, and Broncos fans think it's good luck for the opposing team to pet our mascot".

[4] During a February 4, 1997 press conference introducing the new logo, the team president and the art director for Nike, creators of the new design, described it as "a powerful horse with a fiery eye and mane.

[10] As Thunder II grew older, Magness-Blake anticipated the need for a replacement and added a third gray horse to the team.

[16][17] Thunder shares mascot duties with Miles, a human who wears a horse head mask atop a Broncos uniform.

[13] The horses who have served as Thunder have been trained to remain calm in situations that would normally cause a horse to respond with a fight-or-flight response, such as the flashing explosions of a pyrotechnic display, or items suddenly landing on the field including skydivers with parachutes and various objects thrown by spectators, or loud music and the sounds associated with tens of thousands of cheering fans at Mile High.

[1][18] Ann Judge has explained that because so many unexpected things can happen, it is important that the people working with him remain calm; it is trust in his rider and handlers, not just desensitization, that helps the horse remain steady: "You want them to look to you for the appropriate response and for confidence and faith so that the flight response doesn’t get initiated.

[21] Thunder III is the first of the mascots to tolerate wearing earplugs, which help protect his hearing from loud noises during games.

Thunder responded to the situation with aplomb, continuing to run forward onto the field, though he performed flying lead changes with each explosion.

[23] Thunder appears primarily at home games, but has been transported out-of-state when the Broncos played in the Super Bowl.

[25] He has a large private box stall located next to the visitor's locker room, and has hay, water and treats,[6][26] including a big basket of carrots and apples.

[21] Judge signs autographs for about 45 minutes before each game,[27] allowing fans, particularly children, an opportunity to become better acquainted with Thunder.

[28] Thunder has other duties off the field, and has appeared at many public exhibitions and charity functions in the Denver area, including visits to schools and hospitals.

[18] The day after his arrival in Newark, New Jersey,[33] Thunder was hauled into New York City for television appearances on Today,[34] and Fox & Friends.

[38] For Super Bowl 50, Thunder III was trailered to San Francisco, a two-day trip that took four days because of ice and snow, further complicated by a 24-hour closure of I-80.

[39] Thunder II, who was retired at the end of the 2013–2014 season after the Broncos won the AFC Championship game, had remained in Denver.

On the following Tuesday, he led the team in the Denver victory parade while Thunder III was still on the road heading home.

The mascot's first rider was Angela Moore, then a 19-year-old assistant trainer to Hudson and a graduate of Colorado State University.

[11] Judge grew up on an Arabian horse farm near West Lafayette, Indiana,[43] and graduated from Purdue University in 1980 with a degree in English Education.

[20][31] He served as the Broncos mascot for 11 years and was retired in 2004 after developing arthritis, which made it difficult for him to gallop down the field.

[24] His paternal grandsire is *Salon, a Russian-bred Arabian stallion from the Tersk Stud exported first to Germany and later brought to the United States.

[4] Thunder II would look attentively with his ears forward, seemingly on cue, for his picture to be taken whenever a photographer pointed a camera at him.

[51] When Magness-Blake downsized her horse breeding program, Monarch AH was sold to Zayed bin Sultan Al Nahyan of the United Arab Emirates.

[11] Like Thunder II,[54] he appeared at Magness-Blake's annual Western Fantasy fundraising banquet for the Volunteers of America.