After Ely left the Eraserheads, he would invite musicians and jam together. He had no definite line-up at that time, "I have like 10 members in the band right now, I have 2 drummers, 2 bass players..." according to Ely in an interview with Martin Nievera. This jamming together with friends would eventually evolve to The Mongols. It was composed of guitarist J. Astro (also known as Jerome Velasco) (of The Teeth), bassist Yan Yuzon, drummer Bogs "Boga Man" Jugo (of the indie pop band Daydream Cycle), and Buendia on guitars and vocals, under the stage name Jesus "Dizzy" Ventura. The band was managed by Day Cabuhat, one of Eraserheads' former managers. According to one of the Eraserhead's event producers, Ely's "Jesus" stage name was from an inside joke during the Eraserhead's USA Tour. Ely and Marcus bought replica sheriff badges at the Universal Studios Hollywood and Ely got a badge with the name "Jesus" while Marcus' was "Cesar".
The Mongols released a self-produced underground EP in CD-R format with factory-printed sleeves in April 2003, "A Fraction of A Second". It contains five tracks, "Case Logic", "No", "Tomorrowland", "KSP" and "Abstraction of A Second". It was released under "Redrum Records".
After a few months, the Mongols decided to have their self-produced album distributed by Neo Records Inc. under the major label VIVA Records. The result is a thirteen-track album called "Buddha's Pest" (tracks are: "Keeper," "Bulakbol," "Bakit Nga Ba?," "Pony," "Teka Muna," "Candy Flip," "Heroine," "Wig Out," "It's Over," "Irish Spring," "Odd Even," "Your Bushido" plus an untitled instrumental track). It was produced by "The Genghis Klan" under "Criminal Records".
