Cosmo

12:45 PM. The Toons, as usual, gathered for a long run of eight, boarded a huge elevator, and set off. Louis, Tisha, Shelley, Brightney, Astro, Bessie, Sprout, and Cosmo were there.
Sometimes Sprout, Cosmo's best friend, would fill in for Louie or Tisha and help them "drive Twisteds," which would cause him to lose a heart and be unable to continue running around the map properly. Cosmo would have to heal Sprout and "give" him his own hearts (Sprout can also heal, but with tapes).
After a while, things got really bad. Louis was at 1 heart out of 3, Shelly at 1 heart out of 2, Astro at 2 hearts out of 2, as were Bessie and Sprout, and Tisha at 2 hearts out of 3, as was Brightney. Louis had no stamina left, and Astro's ability to refill his stamina was on cooldown. Because of this, Cosmo gave his last heart to Louis to help him, leaving him with only one. When Louis was down to one heart again, Sprout had no tapes, leaving him unable to help either Cosmo or Louis. He decided to take charge and took the Twisteds from Louis, leading them away from the others and holding them there. He quickly began to run out of stamina, nearly losing a heart.
Seeing this, Cosmo abruptly picked up his 'air horn' from the floor and, pressing it, drew the Twisteds' attention to himself. He ran away from Sprout to help him. Sprout immediately shouted after Cosmo to come back, but he was confident in his decision and still didn't listen.

Cosmo can be shy at times, but it doesn't make him speechless - rather, he just gets confused over his words and so on.
He also usually walks with a calm face, without a smile, but without frowning or seriousness.
Sometimes he can be persistent, but more often than not this 'persistence' sounds like: "Well, maybe after all...?" and the like.
Cosmo is very generous, so much so that his generosity often turns into self-harm, because if necessary, he will definitely spit on his own safety/personal boundaries/comfort limits, step over them and sacrifice himself and his life.
In a children's show, he's the very embodiment of generosity. Cosmo teaches children to share, to be generous, and to help others—but he also, of course, teaches them that if they don't want to share, say, their toys, they don't have to. The key is to simply say, "Sorry, I want to play with my toy now!" and everything will be fine.