What form would a boggart take for Snape?

Per J.K. Rowling's interview, "Telling us Professor Snape's patronus and boggart would give too much away", over at Accio Quote:

Ernie: I wonder if you can let us know what form will Professor Snape's Boggart and Patronus take? I am very curious.

JK Rowling: Well, I'm not going to tell you Ernie, but that's because it would give so much away. I wonder whether Ernie is your real name? (It was my grandfather's).

Since Snape's Patronus is a doe, as a reflection of his love for Lily, and since the Patronus would "give too much away" along with the boggart, we might suggest the latter to be several things:

• Dead Lily. For obvious reasons - Snape thinks he failed her, since he pleaded with Voldemort to spare her, and the latter didn't.

• Dead Harry - less likely, but still possible. Snape sees Harry as his ways of retribution for Lily's death, and a homage to her. Thus, Harry failing his great mission and dying would strike Snape hard.

• Shampoo, as suggested by a Reddit user

• Neville being a Potions professor. Oh, wait...

We don't know, but we can guess.

Ernie: I wonder if you can let us know what form will Professor Snape's Boggart and Patronus take? I am very curious.

JK Rowling: Well, I'm not going to tell you Ernie, but that's because it would give so much away.

_{^{World Book Day Chat}}

Up to the moment of her death, it was almost certainly Lily's death. After that, it was probably everyone finding out his secret shame (e.g. that he caused Lily to be killed) or possibly Harry's death (e.g. the destruction of his last link to Lily).

As Edlothiad has already pointed out, according to Lego Harry Potter (Years 1-4) it was Voldemort.

Although probably not a very good canonical answer, LEGO Harry Potter: Years 1-4 had a lot of the characters have Lord Voldemort as their boggart, including Snape.

However on another note, a very interesting essay on Quora suggests although it's likely to be Lily's corpse immediately after her death, aftr it may have been:

the faces of all of Hogwarts, the students, faculty and staff (and "...especially Potter's son...") all having discovered that James’ death had been Snape's greatest wish and it had come true at the cost of Lily Potter's life.

At this point, this is probably just a superfluous answer, but could it also have been himself?

As he was when he had been a teenager and tormented by James Potter and company.

How many of us possibly hated our formative years as a teenager, especially if we had been tortured and tormented as he had?

As he was when he realized he had caused Lily's death.

That scene seen in his memory when he comes upon Lily's body and realizes what he has done.

How many of us have mistakes for which we wished we had a time turner?

If we could only go back in time and change that one thing? Not the mistake, but everything leading up to it.

As he was when he called Lily a mudblood.

It is, in canon, his worst memory.

Anyway, I'm just throwing the possibility out there since we don't know the canon answer, but at times, we are our own worst enemy, and in the case of Snape, this may be truer for him than it is for most.