Hipbone's size is hard to escape. He's easily the biggest Rock Lord, standing at 13cm high. Most of this is due to the legs, which are also the combined mode legs. They do have a slightly different placement than in the combined mode though, thanks to an octagonal connecting system. They sit slightly higher up the body and wider out in combined form, but they still feel too wide in humanoid mode giving him a 'thunder thighs' look. The squat body and tiny arms adds to this effect.
It's hard to get around Hipbone's odd proportions. He is clearly first and foremost the legs of the combined mode, but at least some effort is put in to make the humanoid mode more presentable, but the leg placement doesn't move enough to be that effective. The rest of him is just strange enough to pull it off, but he's probably my least favourite of the Fossil Lords.