Q: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Rob McElhenney, the actor known for playing Mac in US TV sitcom It's Always Sunny in Philadelphia, has shown off a significant body transformation for the premiere of the show's 13th series.
A:
It's Always Sunny star mocks his 'unrealistic' body change