Despite her small size, Mimipo is block-like and rotund, with a large head and thick legs. Her hide is pinkish-gray, and her eyes are a very dark lavender.
Since she is so young, Mimipo is easily frightened and unable to function on her own. She can be quite fretful in dire situations and finds it hard to cope during such times.
When Timon and Pumbaa come looking for Mimipo, they overhear her crying and come rushing to her rescue. Once there, they try to comfort her by telling her that she can return to the Pride Lands - perhaps even receive a personal welcome from King Simba - but Mimipo cries that she's lost her sister, Sisipo. She then relates how she'd been swimming with her sister when the current had separated them, and now she's gotten herself lost in the jungle.
Seeing the young hippo's distress, Timon and Pumbaa vow to help her find her sister, much to the delight of Mimipo. However, the calf warns them that the current is strong and that fish blow stinging bubbles into the water. Despite the danger, Timon and Pumbaa agree to the adventure, and Mimipo tells them that she can create whirlpools to drive off the dangerous fish.
The three friends jump into the water and swim until they find Sisipo, who has a delightful reunion with her sister.