His masterpiece was a battered ’70s Pontiac Firebird, a flea market rescue with a chipped windshield and faded “Flame Out” decals. The others called it the “Junkyard Jumper.” Leo called it Subject-7 .

Hidden under a painted-on turbo bulge was a micro-switch. If Subject-7 detected a sudden drop in G-force—like, say, going airborne off a loop—the capacitor would dump its full charge into the motor for exactly 0.7 seconds.

In the grease-slicked, low-ceilinged basement of the old community center, the rules were simple. You brought your best Hot Wheels, you ran them on the legendary “Cobra Coil” track, and you prayed to the gods of gravity. For ten-year-old Leo, however, the rules were a cage.

“See? A brick!” Marcus yelled.