Prehistoric mobs, here’s some ideas

So my idea is that kinda like the sniffer each creature preys on another, for example my first idea is a predator for the sniffer, like a thing with a BIG jaw 2 pairs of back legs, 4 small arms, and a big jaw, the mob is covered in red sand, and it can burrow under ground and pop out and attack, sometimes it brings out amber, for other species you can find the egg inside of suspicious sand and gravel, and a new block I call suspicious red sand which spawns in a new structure called mesa temple. idea 2 it would be an extinct caterpillar that lives inside of forests, you can find the fossil inside of trees, by mining these trees with a silk touch axe you can get the fossil and if you place it, and splash regeneration on it, it will be revived, next is a nether fossil, it can be found in souls and valley, I call it the spooker, a shriveled version of it(kind of like the ghastling, if you heat it up with lava you will get a spooker, spookers are half the size of a ghast, but purple, with a sort of beard of fire, and what I call soul rods surrounding it, which you get if you combine a blaze rod with soul sand, or from slaying the spooker. They are aggressive.