Octavia's Contrabass is a unique, pre-war instrument that Blackjack acquired on her travels through the Hoofington wasteland.
The Contrabass was owned by Octavia, a popular earth pony musician who was hired to play the instrument and perform as part of a musical group for events like the Grand Galloping Gala. Octavia played at the gala before her instrument was hijacked by Pinkie Pie who was trying to make the gala more fun and exciting.
During the war
Octavia became less popular during the war, being overshadowed by musician's like DJ Pon3. Octavia's music was also suppressed by Pinkie and the Ministry of Morale, leading Octavia to Flankfurt. She carried her heavy contrabass with her, and was living in Flankfurt before the Megaspell fallout. Rarity asked Octavia to be part of an experiment which would put a piece of her soul into her instrument. Octavia agreed and had half of her soul bound to the contrabass and was escorted home afterwards by Snails. The instrument remained sealed in Octavia's room/home where Octavia herself perished.
Blackjack found the Contrabass and Octavia's remains, along with some of her banned music in her room in Flank. The contrabass was in perfect condition, since it was turned into a soul jar. Blackjack took the contrabass and music, eventually giving the music to DJ Pon3/Homage whilst taking the instrument to Star House.
Blackjack plays the contrabass with her hooves, rather than use her magic, much to her friends' surprise, when she played for them at Star House. She plays it again during a funeral in Chapel, accompanied by regular unicorn music and the Crusaders singing.
Blackjack stores the heavy instrument in her room at Star House in Chapel. Blackjack discovers how the Contrabass became a soul jar during her trip through Hightower Prison. She later gave the instrument to the Crusaders that live in Chapel, so it would be played more often.
Blackjack plays the instrument like an Earth Pony with ease, claiming that it feels right. It also hints that her cutie mark might not represent her true talent, that she might have been destined to be a musician had she not grown up in the rigid system of Stable 99. Blackjack laments this possibility briefly and wonders to herself what else the stable might have stolen from her.
In actuality, the contrabass being a soul jar, embodies Octavia's skill with the instrument, allowing it to play excellent music.
- The Contrabass is a double bass in the canon MLP universe
- Has always been played by hoof and is never shown being used with unicorn magic
- Possibly a reference to the Soil Stradovarius from Fallout 3
- Hinted that Blackjack's special talent might actually be music, when she plays it for her friends
- Is revealed to be a soul jar, the first one created by Rarity using only a piece of a pony's soul
- Due to its nature as a Soul jar, the instrument bestows its users with the ability to play amazing music