Fortune Favors the Bould

A friendly boulder: among 1.4.4+'s boulder mischief there's a rainbow-painted specimen that means you no harm - activate/discover one and it pops. Statistically you'll meet it while tripping the underground's many boulder traps; the unfriendly kind pops Watch Your Step! instead, so either way the caves provide. Chill boulders roll at their own pace.