Why did my mug cake turn out rubbery?

[Kenz]

Hey all, kinda bummed here. Tried whipping up a mug cake last night, but instead of fluffy goodness, I got something closer to a chewy tire. Not sure where I went wrong. Did I zap it too long? Maybe not enough mixing happened? Seriously need your wizardry on this. Any tips?

 

[Babylyn15]

The answer is your mug cake turned out rubbery most likely because it was overcooked or cooked for too long.