Look at his smile

This is a wholesome joke

Well, it could go either way depending on the severity and recency of the irrational fear...

But, to me at least, the teacher seems to be genuienly smiling with his eyes in the selfie.

Exposure therapy can work well with certain fears and traumas that are ... less severe, and more distant in time and space, introduced in a safe environment.

Arguably, the cutesy/cartoonish nature of the hammerhead costumes may also help, and if the kids/students aren't literally swarming and attacking him, but are instead acting completely normal, non threateningly?

That can help to establish that at least depictions of hammerheads are not immediately threatening or dangerous... the only domain it would make sense to be worried about them is where they may actually be present.

I don't see how it could be scumbag. Fear of sharks != fear of people in very obvious and unrealistic shark costumes. People who are afraid of ghosts don't have panic attacks from seeing people in ghost costumes on Halloween.

He does say 'irrational' fear and it was during an ice breaker, I'd take it as wholesome since it wouldn't have been a really serious situation when it was revealed.

Possibility different if they had brought in real hammerhead sharks. Also, if he'd been attacked by a hammerhead shark, but being an irrational fear I'm guessing not.

It's certainly a repost.

It's not like they showed up in his bathtub