Could a cow produce bottled milk? The answer is, of course, no; there is no way a cow could do that; obviously. Perhaps I should be more clear on what I'm asking.
Is there any way a mammalian creature could evolve to create a substance within its body that is somewhat similar to one of the compounds we refer to as glass, give that material a defined shape, and somehow expel it from its body?
In the title, when I say "bottled" I am referring to the classic glass bottles that milkmen would deliver milk in, as seen below.
Of course, the lids on these bottles are made from something other than glass, but just ignore that for now.
So my question is: could a glass making creature exist; and how would it do what it does? (OK, two questions, so sue me.)
P.S. If you're wondering why this question exists or how it came to be, don't; just don't.
Edit: Any scenario that in some way resembles what I described above would be acceptable, the material does not absolutely have to be silicon-based.