After collecting all four Trophies from N. Sanity Beach, you can challenge Ripper Roo. This boss battle takes place on a modified version of Roo's Tubes. Ripper Roo's primary attack involves dropping TNT crates and Nitro crates.
Phase 1: TNT Crates
Ripper Roo will primarily drop TNT crates directly in your path. These crates explode after a short delay or if you hop into them. The key is to avoid them by steering around them or, if you're skilled, hopping over them. He will also drop a few Nitro crates, which explode instantly on contact. Stay alert and anticipate his drops.
Phase 2: Nitro Crates
As the race progresses, Ripper Roo will start dropping more Nitro crates, which are instantly lethal. He will also drop them in more strategic locations, often on the racing line. Your best defense is to stay ahead of him. If you fall behind, be prepared to weave through a minefield of explosives. Use your power slides and mini-turbos to maintain speed and create distance. If you get a shield item, save it for when you're close behind him and need to pass through his traps. Winning this race unlocks the next hub world, The Lost Ruins.