In all of Swallow's appearances, it is shown perching on top of Seaman's shoulder. Though it doesn't play a very large role in any of its appearances, Seaman can be heard talking to it a few times. In "201", when Jesus Christ tells Seaman and Swallow to go get some sushi for dinner, he leaves and says "Swallow, come!" causing the other Super Best Friends to burst out laughing due to the dirty-sounding line.
Like Seaman, Swallow appears to be capable of breathing underwater without drowning.
Swallow has white and gray feathers as well as small black claws. It wears a teal bandana around its eyes.