Answer:
Connotation.
Step-by-step explanation:
Connotation is a meaning implied in a sentence in addition to its literal meaning.
In the sentence, the implied meaning is created by stating that, the high notes of the singer were so painful to the listeners ears that it looked like someone has stabbed his ears a sharp knife, piercing his ears.
As, there is an implied meaning in the sentence, this sentence is an example of Connotation.