The Rebirth system is the late-game progression ceiling. Once a player reaches 50 plots, they can pay $500,000,000 Cash to Rebirth, resetting cash, land expansions, and standard dinosaurs in exchange for a permanent +1.50x multiplier on all future cash generation.
Mythic-tier dinosaurs (Prime Rex and Kraken) and accumulated Teeth survive the reset, which means planning a Rebirth around your Mythic lineup is the single biggest optimization in late-game play.
Most Rebirths should happen right after a Mythic Egg hatch so the Prime Rex or Kraken contributes to post-reset visitor yield. Players should avoid Rebirthing while waiting for an incubation cycle.