a mischievous rival
A mischievous rival is someone who often engages in playful or sneaky behavior to outsmart or annoy their competitors. This person may use tricks or clever tactics to gain an advantage, often leading to friendly competition. Their actions can be seen as both entertaining and frustrating, depending on the perspective of those involved.
In various contexts, such as sports or business, a mischievous rival can create excitement and challenge. For example, in sports, a player might play pranks on their opponents, while in business, a competitor might use clever marketing strategies to attract customers. This rivalry can foster creativity and innovation.