The Many Names of Guita
The dragon had many names, including Guita Boja, La Guita Xica, Mulaguita, La Mulassa, Mula Fera, and Mula Guita.
His name transformed over time. It originally started as Mulassa, then Mulaguita, and finally Guita by the twentieth century.  The name La Mulassa comes from an older term, mulassas, meaning 'monstrous mules,' which was used in Catalan mythology to refer to mule-dragon hybrids. 
Mulaguita is a local name, commonly abbreviated to guita,  which translates to 'kicking mule,'  although in Catalonia, guita specifically refers to a nasty or particularly bad-tempered mule.  His other titles, such as Guita Xica ('Little Guita') and Guita Boja ('Mad Guita') refer to his effigy's function and form in modern festivals. 
Guita was half-mule and half-dragon.  This is because in the Catalan mountains, the mule remains a richly evocative animal. It had a strong practical importance, but it also gained axiomatic status for its temperament, which was disruptive and uneasy to the point where its domestication was considered untrustworthy. 
Thus, all his names refer to his dangerous qualities, as they all reflect the disruptive qualities of the mule. 
Guita was a dragon in the legends of Spain,  sometimes referred to as mule-dragon.  There were references to fabulous beasts dating back to the twelfth century.  The legends of this dragon were believed to be long eroded and lost,  but in 1790, the leaders of Berga city described their effigy of Guita as a tarasca, making him the tarasca of Berga.  The traditions involving the tarasca expanded into the area during the thirteenth century,  influencing the legends of Guita.
One story of the origin of Guita started during the conflict between the Saracens and the Christians, who took a very bad-tempered mule and loaded it with fireworks before sending it to the Saracen camp in the middle of the night. When ignited, the mule's presence terrified the sleeping soldiers, who fled. 
Guita in the Patum of Berga
Corpus Christi festivals include Berga's celebration,  called the Patum of Berga  or La Patum.  It is a popular festival with inheritance from the Middle Ages, and it has a series of performances, parades, and processions in the community.  Historically, many fiery beasts were used in the festivities, including Cerberus, the winged serpent or dragon, and the firework-laden mule. 
The Patum is annual, taking place during the week of Corpus Christi, which falls between the end of May and the end of June.  Various effigies are paraded through the streets, with acrobatic and musical performances. 
To this day, Guita is paraded as an effigy, protecting the inhabitants from evil.  It is made from wood and other materials.  The people carry it aloft as a kind of mock-challenge to the community,  and it is tall enough to reach the windows,  sometimes as tall as a three-story building.  Even in this form, the dragon is chaotic, throwing fire in every direction.  To simulate his fiery breath, the effigy contains rockets, fireworks,  firecrackers,  and other explosives,  which allows the effigy to spit flame continuously. [1,2]
Descriptions of the original Guita were lacking, so the modern effigies of him remain relate his primary traits.
Guita was very large with the basic body structure of a robust equine,  though in some incarnations his body was entirely serpentine.  His head was lizard-like with a long snout,  and his face was black with leering eyes and a gaping mouth with huge fangs.  His neck was long and slender,  extended like many depictions of the Loch Ness Monster.  To this day, he is painted dinosaur-green  or an otherwise naturally occurring green. 
- Guita's name is derived from the colorful nature of the mule's legend in Catalonia. 
- Guita was sometimes called a tarasca. 
- Guita was an original monster, a creature of primeval evil.