Suddenly it twitched...
So correcting my earlier statement, it's now the biggest insect which I saw ALIVE.
Upon closer examination around the crime scene, there were dishes left in the basin with nobody else in sight:
Upon the attack of the great Cicada, lady X was forced to leave her dishes and flee. 當某女生甲被蟬攻擊時，她匆忙地留下還沒洗完的鍋碗，然後火速地逃離現場。While fleeing, she had probably inflicted damage to the Cicada and caused it to faint. But due to the great trauma, lady X decided to just leave her dishes there and return the next morning.
That's my hypothesis, hmm...