Season 1, Episode 37br br In the original ThunderCats series, Lion-O undergoes the Anointment Trials to prove his worthiness as the Lord of the ThunderCats. br br The first of these trials is the Trial of Strength, where Lion-O must prove himself stronger than Panthro. During this trial, an earthquake causes a large boulder to roll towards Wollo Village, endangering the villagers. Panthro is injured while attempting to stop the boulder, but Lion-O manages to save him and roll the boulder away, thus demonstrating his strength and passing the trial.