Solid Mobs Add-on 1.21+

Sometimes Minecraft's game mechanics can be surprising. With the Solid Mobs mod, all creatures become your platforms. You can stand on mobs, stack them on top of each other, and build unusual structures, turning the ordinary world into a testing arena.

Now you can use any mobs as platforms, stack them into towers, and create creative parkour tracks. This opens up new possibilities for creations and amusing experiments.