Symbolism, Imagery, Allegory
Tyro drives a very fancy SUV, a "Cadillac Escalade, white, top of the line" (10.70). It is a status symbol, of course, but to Bart, the car is a stand-in for Tyro himself. So after Bart gets a text from Tyro in which Tyro pretends to be his dead father, he decides to exact revenge. Knowing he can't really do anything physical—"I was outnumbered. I had no allies, no backup" (8.19)—Bart lands on the Escalade as the next best thing. He even carves "Tyro the Terrorist" (8.29) into the paint job.
For more on the terrorist bit, be sure to read up on Tyro as a symbol in this book. Our boy Bart definitely feels terrorized, and for better or worse, Tyro takes a lot of the blame.