Disney animator and imaginer Francis Xavier Atencio, known for his work on films including Pinocchio and classic rides such as Pirates of the Caribbean, passed away on September 10, 2017. He was 98 years old.

Known best as simply “X,” Atencio went to work for Disney starting in 1938, taking a brief leave of absence from the studio to join the Army Air Corps in WWII. Pinocchio was the first film he was involved with, and he later moved onto Disney short films including A Symposium on Popular Songs, Jack and Old Mac and I’m No Fool, among many others.

He was transferred from the animation studios to WED Enterprises (known today as Walt Disney Imagineering) at Walt Disney’s personal request, where his first project was on the Primeval World diorama for the Disneyland Railroad. He later worked on the script for the Adventure Thru Inner Space attraction in Tomorrowland, and for Pirates of the Caribbean in Adventureland. He was also responsible for writing the classic theme song for the latter attraction, “Yo Ho (A Pirate’s Life For Me)” and provided voices for many of the characters in the ride as well.

Atencio’s influence can also be found in another classic Disney attraction, the Haunted Mansion, for which he wrote both the script and the lyrics for “Grim Grinning Ghosts.” For Walt Disney World in Florida, he was involved with the development of Spaceship Earth and the Mexico pavilion at Epcot, plus the now-retired If You Had Wings and World of Motion.

Though Atencio retired in 1984, he continued serving as a consultant to Walt Disney Imagineering for many years; he was inducted as a Disney Legend in 1996.

“X was an enormous talent who helped define so many of our best experiences around the world,” said Bob Weis, president of Walt Disney Imagineering. “Some may not know that when he wrote the lyrics for ‘Yo Ho’ he had never actually written a song before. He simply proposed the idea of a tune for Pirates of the Caribbean, and Walt told him to go and do it. That was how X worked—with an enthusiastic, collaborative attitude, along with a great sense of humor. His brilliant work continues to inspire Imagineers and bring joy to millions of guests every year.”