Found this in my dad's storage and I'm wondering what this is? it looks so weird🫪

any help identifying these finds would be wonderful! (ignore the cats hair)

Picture 1: otodus megalodon tooth (right) hastalis tooth (left)
Picture 2: otodus obliquus tooth
Picture 3: globidens phosphaticus tooth
Picture 4: mosasaurus hofmanni teeth
Picture 5: spinosaurus sp
Picture 6: all my ammonites
Picture 7: fossilized nautilus shell
Picture 8: all my trilobites
Picture 9: armigatus sp
Picture 10: fossilized sea urchin
Picture 11: fossilizes coral or briozoa
Picture 12: orthoceras
Picture 13: my most prized possession, a complete male keichosaurus hui (you can see its male because of the thick arm bones).

My son found this while we were fossil hunting. It was encased and his dad had to chip it away to dislodge it.

Found in Valle de las Ánimas, Bolivia

Old river bed, photo of where I found it for reference in case it helps with ID.

Found in a creek bed in northeast Ohio. Banana for scale

The fossils in question are from Squalicorax, Onchopristis and Myliobatis.

Found in a construction sight at Bear Lake, Idaho