what if as part of using my primal form for fighting things i just smoothly, rapidly shifted between the big kaiju-like version and an anthro version. really get some shapeshifter shenanigans going on with it
i mean part of it is that the size of the big version is influenced by how much magic i've got available, so by condensing that down all that magical 'mass' would just go into being super dense and nearly unbreakable even before you get to the innate durability enchantments etc