"They think he is kind of creepy." Armin watches as Gus examines Marceline's extended hand for a moment, before wrapping his thin fingers around hers. Yes, he knows how to shake. He has seen the human people do it. Of course, being that he is a fungus boy, he doesn't quite manage a proper shake. Rather than a good solid hello, Gus' shake ends up being more of a weird tickle against Marceline's palm, moving her hand up and down in a slow manner. He also holds on far too long.