Imagine a Souls boss that is just some old gramps in a wheelchair rolling away and summoning ghosts to beat you like the Tibia Marine.
Once you smash his wheelchair he collapses to the ground, but just a few seconds later his body stands up like he never had an issue standing. He turns the broken remains of his wheelchair into pic related and starts to 1on1 you, turning into a nimble maniac.
Only when you beat him, you see that he summoned a puppeteer ghost to control his body, fading away.