The Slug Crawler Vehicle is a totally sealed rescue robot that can go anywhere that a squishy robot can go. Developed at the Chiba Institute of Technology in Japan, its flexible skin is manipulated by internal robotic parts to move around (see video below).
(Slug Crawler Robot Has Retractable Skin)
You can sort of think of the robot like a little tank, except it's just one big flexible tread that wraps around the entire body. Steering is accomplished with two internal pulley systems that can swivel from side to side (it's the silver one in the pic above). Together, they pull the tread into an arc shape to change the direction of movement. It's robust, reliable, and completely protected against dirt and water, making it a (potentially) very effective search and rescue robot.
Fans of the sixties TV series The Prisoner remember the Rovers, mysterious squishy surveillance robots.