Sharpshot is the Terrible Terror that Hiccup trained in the episode Worst in Show. He is considered to be the second dragon that Hiccup has officially trained in the series.
Some fans believe that Sharphot is the same Terrible Terror from Dragon Training in the How To Train Your Dragon movie as they look exactly the same, but this can't be denied or confirmed.
It is possible that the Dragon Training Terrible Terror and Sharpshot are both based off of Toothless in the books as he matches Toothless' description in color, size, behavior and overall design.
Sharpshot is also the only trained Terrible Terror that is shown to have more than one skill.
Sharpshot reappeared in "[[w:c:howtotrainyourdragon:Appetite for Destruction|Appetite for Destruction]" as an "air mail" delieverer. He first delievered a letter to Fishlegs and Snotlout to meet Hiccup and Astrid on Dragon Island. He then delivered a message to the twins and Snotlout warning them about the Screaming Death.