The Host foresees his arrival and insists that Wilford and Bim are with him when the poor thing is due to arrive. He doesn't know the details, just the time and place.
The stranger is snarling and, for lack of a better term, seemingly feral. When he lands, he's covered in deep scratches, and his arm hangs in a way that suggests something more is wrong beyond the immediately evident.
Whenever they try to come near, he just finds another way to get away from them and they soon realise, he isn't attacking them, he's running away. So they decide to try and corner him.
Wilford is the one who manages to trap him, and as Bim and the Host join him they can see him properly. His smart shirt is torn and his smart trousers are missing a leg; there's a fairly bad injury on his exposed shin. As they draw closer, he reaches to hold his arm, the one they suspect is badly injured and glares at them, giving a low growl.
Then something shifts, the Host feels it, and the fear is gone replaced by confusion as he shuffles back some more.
"Will?"
The Host can just feel this is going to get worse before it gets better and signals to Bim. The TV show host raises his hand that glows purple as he guides the poor thing to sleep with extreme encouragement.
Wilford carries him as they use the pink man's void to return to the building, the Host confused by the fact that this stranger seems to have recognised one of them. Given the highly anxious state that the man was in when he was knocked out, any foray into his mind would be hard to traverse. Better to wait until he wakes up and can comply.
Despite being a fully grown man, just like the rest of them, he almost seems like a child in Wilford's arms. They bring him to the clinic, allowing him to rest in a bed there for a short while. It's almost an hour before he stirs, the Host using his narrations when he feels the poor man's panic begin to rise.
"As you gaze at the strangeness that surrounds you, you come to realise that you are in no danger. You feel safe and secure in the knowledge that they cannot harm you here. And when you look at your hands you notice-"
The Host stops as he knows what he's about to narrate, immediately reaching for the stranger's shoulder, using his powers to look inside his mind.
He sees everything, where he came from, what he's been through, who he is and the Host stumbles back in shock. Yelling for the doctor he instructs him to fetch Dark immediately
A panicked hand grabs his sleeve; the man's, and he looks up at the Host in shock, demanding answers. The Host merely grabs the stranger's hands and holds them in front of his face telling him to look. Look at your hands. Look at yourself. Look!
His eyes go wide as he sees them, as though he's seeing them for the first time, turning them over and over in astonishment, wincing when it pulls at his shoulder. He demands to know where he is. What's happening? Who are they?
That's when Dark shows up, his presence commanding the attention of everyone in the room, the color draining around him, the ringing sounding high-pitched and piercing. The stranger is afraid and tries to get off the bed, but Bim, who's moved to stand beside the bed, holds him down.
The stranger, the Host tells them, is Dark, from another reality.