A rattlesnake.
it look like a round worm
it looks like a normal worm there's no difference
a bit like a worm
They look like a snake.
There is no species called the "desert rattlesnake" but there are dozens of species that live in the desert. The image above is one of them.
it is ugly
a rattlesnake uses mimicry to look like other animals
See the image above of an eastern diamondback rattlesnake.
because they look like worms accept they are grey and herbivore. (plant eater)
a willy worm looks like a catarpillar with black "spikey fur"
It looks like a flying red worm
Rattlesnakes bear live young, they do not lay eggs.