I had a substitute biology teacher in high school who was really socially awkward. Like he kept trying to get us interested in seeing the snail collection he had in the courtyard. He subbed for us rather frequently and you could tell he was new. We high school kids took advantage of that (obviously) and several weeks in you could tell his nerves were fraying.

One day we were dissecting frogs and the sub was making the rounds from table to table asking the kids what gender their frog was and how they could tell. For instance, mine had eggs so female obviously.

We were all chatting, waiting for the teacher to come around. The class was getting pretty bored and loud and the poor guy was too shy to try to calm us down.

He got to the lab group next to us.

Teacher: So what gender do you think your frog is? Student: Um, female? Teacher: Why do you say that? Student: I can't hear you. Teacher (louder): Why do you think it's female? Student: Because it has nipples.

And this was that moment when you have your voice raised and the crowd goes quiet for no reason.

Teacher (loud): Well I have nipples.

There was an awkward silence.

The sub, his face red, coughed. The class was quiet. Finally one of his students saved him with the right answer. He moved to our desk and continued the lesson, his voice quiet, the class subdued.

The next day our sub was an older woman. We never saw the poor guy or his snail collection again.