Did Professor Severus Snape know how to transfigure into a bat?

Question

First of all, I'm not asking for evidence whether Professor Snape was a vampire, or if he was an Animagus, or if he could fly. I'm curious if he knew how to transfigure into a bat using any magical mean (drinking a potion, casting a spell, etc.).

Again, and to make it simple, my question is: Does Snape know how to transfigure in a bat?

The prior question: Can Snape fly without metamorphosis? is different from mine. I am not asking if Snape can fly.

I am bringing the bat transfiguration based on the possibility that Snape himself or Voldemort or Dumbledor or someone else taught him how to transfigure in a bat. Let us remember that in case that Voldemort taught Snape how to become an animagus, Snape was unregistered.

Regarding the transfiguration into a bat, there is a reference from J.K. Rowling in chapter one of Quidditch Through the Ages (2001), about a 'Human to Bat' spell, but according to Kennilworthy Whisp, this was one of the few ways wizards could fly unaided but, it was inconvenient because a bat lacked the memory required to remember important things.

No spell yet devised enables wizards to fly unaided in human form. Those few Animagi who transform into winged creatures may enjoy flight, but they are a rarity. The witch or wizard who finds him or herself Transfigured into a bat may take to the air, but, having a bat’s brain, they are sure to forget where they want to go the moment they take flight.

In other words, in the Harry Potter universe exist at least one spell to transfigure a human into a bat.

There are several references in Rowling's Harry Potter Volumes where it is said that Snape "looks like a bat" as follows:

In Volume 7 of Deathly Hallows, Chapter 30 'The Sacking of Severus Snape', Snape used his skills to escape from Hogwarts after his duel with Minerva McGonagall:

"No, he's not dead," said McGonagall bitterly. "Unlike Dumbledore, he was still carrying a wand...and he seems to have learned a few tricks from his master." With a tinge of horror, Harry saw in the distance a huge, batlike shape flying through the darkness toward the perimeter wall.

Harry Potter and the Half-Blood Prince, Chapter 9:

Neville's muttered Jelly-Legs Jinx without uttering a single word, a feat that would surely have earned her twenty points for Gryffindor from any reasonable teacher, thought Harry bitterly, but which Snape ignored. He swept between them as they practiced, looking just as much like an overgrown bat as ever,...

Whit the information above, I'm curious if there's a canonical answer to whether Snape knew of or created a potion or knew a spell or other art that could transform him into a bat.

Answer 1

Voldemort learned to fly without support. We don't know how, exactly, but he is depicted to be flying without a broom in the seventh book.

And then Harry saw him. Voldemort was flying like smoke on the wind, without broomstick or thestral to hold him, his snakelike face gleaming out of the blackness, his white fingers raising his wand again —
_{Harry Potter and the Deathly Hallows. Chapter Four. The Seven Potters.}

And it is implied that Snape learnt the trick from Voldemort. Minerva McGonagall, being an expert on Transfiguration, would've likely recognized any attempted transfiguration to fly. Since she didn't mention it, it is safe to say that Snape performed the same spell as Voldemort, or a similar one.

Harry dragged her to her feet and they raced along the corridor, trailing the Invisibility Cloak behind them, into the deserted classroom where Professors McGonagall, Flitwick, and Sprout were standing at a smashed window. “He jumped,” said Professor McGonagall as Harry and Luna ran into the room. “You mean he’s dead?” Harry sprinted to the window, ignoring Flitwick’s and Sprout’s yells of shock at his sudden appearance. “No, he’s not dead,” said McGonagall bitterly. “Unlike Dumbledore, he was still carrying a wand . . . and he seems to have learned a few tricks from his master.” With a tingle of horror, Harry saw in the distance a huge, batlike shape flying through the darkness toward the perimeter wall.
_{Harry Potter and the Deathly Hallows. Chapter Thirty. The sacking of Severus Snape.}

Answer 2

Possibly, yes.

We might even be able to say "probably".

It's not clear from the books the extent of Snape's magical knowledge, but he has shown on several occasions that he is an extremely skilful and competent wizard. Not only has he ever struggled with any of the magic he was shown attempting, but he also was able to invent spells of his own - such as Muffliato, Sectumsempra, and Levicorpus, according to The Half-Blood Prince - which implies a certain level of magical mastery.

We do have some examples of non-Animagus human-to-animal transformation shown in the books. For example, the following cases in Goblet of Fire:

• Barty Crouch Jr transforms Draco Malfoy into a ferret
• Viktor Krum transfiguring his own head into the head of a shark

We don't know whether it's more difficult for a wizard to transfigure himself into an animal compared to transfiguring someone else. Krum seemed to have more difficulty in his case, but that could be due to the fact that he is still a student, as opposed to a fully mature and competent Crouch Jr. Suppose we can safely assume that self-transfiguration is not significantly harder than applying the transfiguration on another target.

We don't know whether transforming a person into a bat is any more difficult than transforming into a ferret, but it's reasonable to assume that it would be not much different. So, let's look at the ferret transformation for now.

It's possible that the ability to transform a human into a ferret is extremely uncommon, and that Crouch Jr (posing as Professor Moody) was only able to do this transfiguration because he is an uncommonly gifted wizard. However, this seems unlikely, based on Professor McGonagall's reaction when she saw the transfigured Malfoy:

“Teach — Moody, is that a student?” shrieked Professor McGonagall, the books spilling out of her arms. “Yep,” said Moody. “Moody, we never use Transfiguration as a punishment!” said Professor McGonagall weakly.”

Her words only revealed shock at the choice to carry out this magic, not at the ability itself. It almost implies that she believes that anyone at the level of Hogwarts professor could reasonably be expected to be able to perform the transfiguration, but should never actually do it (at least, not as a form of discipline).

If turning a human into a ferret (or a bat) is not an extraordinarily complicated piece of magic, and Snape is capable enough that he can perform any ordinary level magic (as well as at least some extraordinary magic), then it's likely that Snape has the knowledge and skill, at least, to be able to turn himself into a bat if he wanted to.

Whether he ever would choose to do so or not, however, is a different question. It's probably unlikely, because Snape seems sharp enough to be aware of the disadvantages of this transfiguration as mentioned in Quidditch Through the Ages.