Lion-O's Anointment First Day: The Trial of Strength is the thirty seventh episode of ThunderCats (original series). This is the first episode in the story arc "Lion-O's Anointment Trials".
It is Lion-O's 20th birthday, and he is excited not only because of the birthday but because he is now to be crowned the Lord of the ThunderCats. When he wakes up, he finds Cat's Lair deserted except for Snarf, who advises him to eat as much as possible as he has a long journey ahead. Snarf explains that while Lion-O is the hereditary Lord of the ThunderCats, he must prove himself to be worthy of that title. To that end, he will be expected to face each of his fellow ThunderCats in an anointment trail, and by besting them all he will prove his worthiness. Lion-O is shocked to find that the Sword of Omens and Claw Shield are missing, and Snarf explains that the trials must be faced unarmed.
His first test is to beat Panthro in a duel to test his strength. Lion-O tries to dodge Panthro's blows and then tries to fight back, and the two are almost evenly matched. The trial is interrupted when there is an earthquake and rocks are sent flying towards him. Panthro is trapped beneath a large boulder and cannot free himself. Lion-O runs to help him and manages to life the boulder away himself. Panthor is satisfied that Lion-O has proven his strength, and hands over the ThunderCat emblem from his belt. Lion-O continues on his way to the next trial, where Cheetara waits.
- Cats Lair
- Plain of Fertility
- Acid Lake
- The Great Void
- Silver Cliffs?
- Beach of the Crabmen
- Wolo Village
- Whilst Lion-O is talking about what he needs to do to pass the Trials, the footage shown of Panthro, Tygra and the ThunderKittens is taken from the "lost intro" from the "movie" version of Exodus, the Movie.
- This episode is one of very few in which Liono-O does not perform the famous "ThunderCats Ho!" chant.
- This is the only one of the five Anointment Trials episodes not to feature either Mumm-Ra or the Mutants. The Mutants--Slithe the Reptilian, the Monkian, and the Jackalman--do, however, attempt to disrupt the Anointment Trials of Speed, Cunning, and Mind-Power, and the Anointment Trial of Evil has Lion-O facing off directly against Mumm-Ra.