A Rock Friend, Indeed is an episode of the Unikitty! animated series.
Puppycorn goes looking for someone to play with, but finds that Richard, Hawkodile, Dr. Fox, and Unikitty are all busy. He then announces his intent to hang out with "Rock Guy", whom Unikitty discovers is an actual rock. Horrified that her brother's only friend is a rock, Unikitty decides to hide Rock Guy and encourage Puppycorn to find a new friend. Sadly, his efforts prove less than successful, but he is inspired when his sister suggests that he "make" himself a friend.
The next morning Unikitty and company awake to find that Puppycorn has taken several of their body parts to create "Friend Guy", a bizarre creature that soon begins adding Unikingdom objects and citizens to its form. Unikitty, initially unwilling to take action due to Puppycorn's affection for him, soon finds herself forced to contend with the kleptomaniac creature. However, after both she and Puppycorn are captured, they are saved when Rock Guy-inexplicably communicating with Hawkodile-is flung into Friend Guy's path and causes it to trip and break apart. Unikitty then celebrates things working out, despite the fact that she and her friends are still without their stolen body parts.