Acie

It feeds by grounding itself against charged metal and drawing current in rhythmic pulses, its spines flickering in time. Those spines discharge on contact, so a predator that grabs an Acie gets a sharp lesson and an Acie gets to walk away, unbothered, still humming. It is a fidgety, restless thing, forever repositioning to find a better source of charge, and colonies of them near the Tower flicker and pulse out of sync in a way that, watched long enough on a dark night, is oddly hypnotic.