I've encountered an unusual shape that I have no idea the name of. We have a sticker on the shape that tells us the equation $z^2 = \frac{x^2}{a^2-y^2}$
Here is a picture of the shape itself: https://i.stack.imgur.com/4dCJr.jpg
edit: i realized it might be a bit tough from just one angle so here is a second picture https://i.stack.imgur.com/1FibB.jpg
On the tumblr link above, it's called a wedge-shaped cylinder. Interestingly, this shape is talked about on p. 222-225 of Magnificent Mistakes in Mathematics by Posamentier and Lehmann, 2013. They don't provide a specific name for the shape though.
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