Ricardio is Ice King's heart where he first made his appearance in the episode "Ricardio the Heart Guy." In the episode, Finn was jealous of Ricardio because he was with Princess Bubblegum talking about science. Finn then suspected that he was evil. It was explained by Ice King that he made a love potion for Princess Bubblegum's heart so she can fall in love with him (Ice King) but he lost control of his. In the episode "Lady & Peebles," it is revealed that he has reformed. He is defeated by Princess Bubblegum, and runs away. His current whereabouts are unknown.
His body is shaped like a "love" heart, and his face is extremely detailed, unlike most characters. His face looks sort of evil, and menacing.
- Ricardio wants Princess Bubblegum because he is the heart of Ice King, who wants Princess Bubblegum.
- Being a heart, he doesn't look like an actual heart. Instead, he looks like the 'love' heart.
- In the original designs, he looked like a real heart.
- He has the most detailed face in the series.