ThunderCats S01E46 - Lion-O's Anointment Third Day The Trial of Cunning

Lion-O must now face off against Wily Kat and Wily Kit. It's a race through a cavern, with Wily Kat and Kit, playing tricks on Lion-O. They must also contend with Mutants, and Lion-O meets a race who dwell in the caverns and who don't like people from the outside.