In "Hot Diggity Doom," the King has regained his "zep" and his following thanks to help from a mysterious helper who turns out to be Orgalorg. He successfully runs against Princess Bubblegum for control of the Candy Kingdom (even getting Sweet P back on his side), winning in part because she is too preoccupied with the Catalyst Comet to campaign against him, as well as Bubblegum creating the Candy People with low intelligence to eliminate any potential dissent against her rule, rendering them unable to realize the difference between a good leader and a bad one. The kingdom then almost immediately descends into chaos as the Catalyst Comet arrives. The king immediately realizes this and was saddened when he thought that it was his fault. Toronto consoled him and he came to the conclusion that it was Princess Bubblegum's fault. He is ruler of the Candy Kingdom from the end of "Hot Diggity Doom" to "The Dark Cloud" when the Candy People choose to rebel against his leadership, and Crunchy pushes him into a fireplace, taking the throne. The King of Ooo is flees through the candy streets as an amorphous blob of earwax and eventually reforms into a child-like form known as "Waxman of Ooo" as seen in "Come Along With Me".
The King of Ooo is a tall golden being with thick puffy golden brown hair (which is revealed to be a toupee in "The Dark Cloud") and a mustache, along with a single mole on his face. He wears a broad-shouldered brown coat with gold trim and several gold rings, which has a lighter brown pair of pants and button-down shirt beneath it, along with a crown. He carries a scepter with a winking smiley face on it. According to the Adventure Time crew, he is made of earwax; this is confirmed by the King as he mentions his "waxy heart" in "Hot Diggity Doom". In "The Dark Cloud", Crunchy pushed him into a fireplace, reducing the King of Ooo to a melted pile of goop. As the Waxman of Ooo in "Come Along With Me", he is bald and short, wearing only a leaf.
- Melting: Because he is composed of earwax, when unsheltered in high temperatures, he melts instead of burning, turning into a gooey substance.
- Reformation: After melting in "The Dark Cloud", he reforms into a new, more basic form known as "Waxman of Ooo" at some point before "Come Along With Me".
- "Hoots" (cameo)
- "The Comet" (cameo)
- "Bonnie and Neddy"
- "May I Come In?
- "Take Her Back"
- "The Dark Cloud "
- "Ring of Fire" (flashback, cameo)
- "Come Along With Me" (cameo, as Waxman of Ooo)
Princess Bubblegum does not accept his authority as a king. Also, she personally dislikes him, even going so far as to break into his blimp to search it and prove him a fraud and con man. There she finds an expired certificate stating his right as a priest for Tree Trunks's wedding. She tries using this as a reason to arrest him, but is proven wrong when the King Of Ooo tells her she probably found it in the old section of his blimp, and pulls out a new certificate out of his pocket. Princess Bubblegum nevertheless has him arrested and thrown in the Candy Dungeon, along with the other attendants of the wedding when they protest her poor behavior and refuse to recognize her authority.
Despite Princess Bubblegum's animosity towards him, Tree Trunks and Mr. Pig do apparently recognize him as "the One True King of Ooo," along with a number of their relatives. He is shown making metaphorical declarations to Mr. Pig's relatives, such as interpreting their imagined "thought-forms" and granting "one year good luck" to them based on their "visions." In addition to the support of various individuals, the King of Ooo also works closely with his companion Toronto. In "Gold Stars," they both work together in robbing the people of the Candy Kingdom.
The King of Ooo usurped Bubblegum's throne through a "barely yet fully legal" election and was temporally the ruler of the Candy Kingdom. He likely did so as revenge for locking him up in "Apple Wedding." At the end of the miniseries "Stakes," the Candy People rebel against the King of Ooo's regime, and Crunchy usurps the throne. At the end of the episode "The Dark Cloud," Princess Bubblegum states that she intends to usurp Crunchy and re-gain the Candy Kingdom.
Personality and traits
Generally, the King of Ooo maintains the appearance of a benevolent ruler. He does this by acting kind and amiable in front of his "subjects." However, this act is in order to to exploit his followers for his personal use. This is seen in "Apple Wedding" where the King's dubious authority includes a clause in the wedding vows that would have made Tree Trunks and Mr. Pig his servants for five years.
Because the rulers of the various "kingdoms" in Ooo are princesses, it is probably more accurate to say that Princess Bubblegum (as well as all other regnant princesses) is the ruler of a principality (The Candy Principality) that in turn would be subject to the sovereign to a king of Ooo. Principalities (in the real world) can be sovereign, but more often than not the prince or princess of the realm is subject to the King. The fact that Princess Bubblegum does not recognize his authority likely means she does not recognize Ooo as being a unified Kingdom and views her principality as sovereign.
The true nature of the King of Ooo can be clearly seen in "Gold Stars" as he is willing to use Sweet P, an innocent child, for personal gain. In the episode, the King abducts Sweet P from his school and pretends to be his dance teacher. He then uses the boy to distract random Candy People so that he can easily steal their valuables. In addition to theft, the King of Ooo was willing to "take care" of Sweet P when the boy discovered that the King was merely a criminal.
- The King of Ooo is also the namesake/mascot of the Tumblr blog for the Adventure Time crew, kingofooo.tumblr.com.
- In the storyboard for "The Tower," the King of Ooo's crown appears as one of the objects Finn uses to build his tower.
- His exact political power is debatable, as he was imprisoned by Princess Bubblegum who, under normal circumstances, shouldn't have the authority to do so.
- However, she did appear to do so by force and without warning, and he had no security to help.
- He claims to own the sun.
- His supposed position and following appear to have elements of a cult, as he has many followers who supported him in his election to be Princess of the Candy Kingdom and oppose Princess Bubblegum's rule.
- This is reinforced by Tree Trunks' devotion to him and her apparent requirement of working for him as servants for a set number of years in an unknown facility.
- In "High Strangeness" a propoganda-like poster of the King of Ooo is seen in the meeting room for the Veritas Brigade , a group of insurgents opposing Princess Bubblegum including Starchy, Tree Trunks, and Nurse Pound Cake.
- In "Ocarina", a statue of the King is seen in Kim Kil Whan 's home, implying he is a follower of the King of Ooo.
- A wanted poster for the King of Ooo is seen at the Candy Kingdom Police Station in "Ocarina".
- When you go to kingofooo.com, it directs you to Cartoon Network's main page.
- As of "Gold Stars" he seems to have lost most, if not all political power he may have had, as he is seen living in a slum with Toronto and claiming he will make a comeback. This happens in "Hot Diggity Doom" thanks to help from Orgalorg.
- As of "Hot Diggity Doom," the King of Ooo has taken control of the Candy Kingdom. It is unknown, however, if any of the other kingdoms recognize him as the leader and a hero who removed a tyrant from power, or view him as an insurgent who usurped the throne out of spite. He is also not a registered princess, and likely never will be for reasons relating to gender and criminal background.
- However, as of "The Dark Cloud," Princess Bubblegum is regaining authority within the Candy Kingdom, and Cruchy exiled King of Ooo away from the Candy Kingdom.
- To assert his authority as the "Princess", he wears Princess Bubblegum's clothes around.
- While hunting, The King of Ooo shot arrows with cotton balls instead of arrow heads. This is obviously a joke on the fact that cotton swabs are used to remove ear wax, which to him would be the equivalent of being stabbed or shot at.
- He has an opposite gender version called Queen of Ooo that appeared in "Fionna and Cake and Fionna"
- In the series finale "Come Along With Me", it is shown that BMO uses his name in around a thousand years as a legendary title to travelers.
- There is also a statue of him in BMO's new home at Mount Cragdor.