Mr. String is a long, slender piece of blue string. Although he is kind, smart, and helpful, he can be very pessimistic and worries about his fortune and his friends' actions and thinks the results would be "Definitely! Definitely!". Regardless of his positivity, he likes teaming up with Mop to look after Plush, Bob the Ball, and Little Cup as well as showing of his creative side.
- Nervous Wreck (Loud, Soft, Shake & Rough, Smooth, Picture)
- Doin' the Thin Thing (the rest of Season 1)
- I'm Jumpy! (Season 2)