Mercurious

As he closes the restroom door I start to think if this was a bad idea, especially when he pulls out a knife from his back pocket. "Wait what the hell are you doing?" I ask while eyeing the serrated knife in his right hand as he pulls up his left sleeve. "Showing you," Billy says, looking at me then slicing it across his arm and wincing in slight pain.
Looking down in shock I see the same silver liquid that courses through my veins, leaving his skin. "Who are you?" I ask turning on the sink faucet so he can wash the shiny liquid away, "Oh, actually that won't be necessary." Then I watch in awe as Billy puts the knife on the counter and slowly waves his hand over the cut. Beads of sweat started to form on his forehead as he repeated this motion. He looks constipated. Then suddenly his hand starts to glow green and the wound begins to close up. Holy shit! Man, how come I can't do that? "H-how the hell did you do that?!" I asked, grabbing his arm and turning it over to inspect.
Silently chuckling he says, "I'm not entirely sure but I'm different and non-human, like you." "Non-human..how, why?" "I'm not sure but if you come with me I can show you where others like us are." He says while holding out his hand to me. Hm, if I go with him all my questions might be answered. . .