Bone shaped ice mold.

Sculpted manually, no ai ;)

Do You want another shape?

No problem, for simpler models, which can be prepared and easily removed from a 2-element ice mold, you can use Universal Ice Mold Creator, which allows You to create almost any shape ice rocks.
Universal Form Generator for Any-3D-Shape Ice-Mold

or get ready model:
ice mold - skull shape

brick ice mold tray or single brick

Version 1 : small water leaks, additional rubbers required to push both sides together

Version 2 : no leaks, but quite difficult to open

Attached 3mf file with minimum material use. This scenario is quite soft. This make this model harder to open and easier to break when opening. You may also use default settings to make model inflexible.

To avoid water leaks, use a few rubber bands and put them into the refrigerator on a plate or bowl!

I bought my blue TPU here: [https://s.click.aliexpress.com/e/_EJuLTIo](https://s.click.aliexpress.com/e/_EJuLTIo)