[[WMG: Robert is actually a mass of angry, psychic dinosaur ghosts.]]
Rubber is made of petroleum, which is made from fossils. Robert is a tire haunted by the ghosts of the dinosaurs the fossils of which became the petroleum used to make Robert. They are angry that they are all jumbled together in a synthetic object, and have psychic head 'splodey. He's obsessed with the female motorist because [[JurassicPark Humans are delicious]].