Answer:
Irony being the opposite of what is or can be expected, I guess it could be how the cub Simba can't wait to be king and they dedicate a whole scene and song to it, yet Simba's life takes him to a point wherein he abandones his identity as a king and eventually literally denies that he is the king.
The cub Simba: "I'm gonna be your mighty king, so enemies beware. I'm gonna be the main event like no king was before. ... Oh, I just can't wait to be king!" The adult Simba: "No, I'm not the king. Maybe I was gonna be but... that was a long ago." "We talked about this, I'm not the king, Scar is."