This is not a bad idea, it is just a little useless.

Imagine a worm that has a head and alternating segments. 

Some of these segments are made of a material that expands a lot when heated. These segments have many resistances attached to them, so they can be heated. 

The other segments are photovoltaic modules that get solar energy to power the worm. 

On the head, there is a microcontroller that oversees the operation. 

The microcontroller powers the resistance segments in an alternating form, as to produce linear motion on the worm. When a section is expanding, the section in front of it is contracting, and a displacement wave travels through the worms' body. We've all seen bugs like this. 

And that is it, just a very slow way of getting from A to B. Please don't make them poisonous.