Mr. Jelly

Mr. Jelly is the fifteenth book in the Mr. Men series. In the US version he is called Mr. Nervous

History
Mr. Jelly is afraid of everything and anything, such as the snapping of a twig, a sound of his cereals or a small worm. He often hides under the covers. One day, he finds a tramp sleeping in the field near the woods, whom he is afraid of, until the tramp teaches him to count to ten if he feels nervous. This makes Mr. Jelly a calm fellow and he rarely hides under the covers now.

Mr. Jelly's nervousness is understandable given that he is only a few inches tall - small enough for the tramp to hold in his hand. Most other Mr. Men/Little Miss characters (excepting Mr. Bounce, Mr. Small and Little Miss Tiny) are roughly the same size as ordinary humans. He is very light too. He is afraid of all the sounds (include of his cereals).