It's probably best to go to the Pokemon expert. Your best friend probably doesn't understand Pika-language and probably out on vacation. You make your way to the Pokemon expert's house.
You stop at a small, comfy-looking house, which is the kid's home. You go on up to the front door and ring the bell. Ten seconds later a somewhat scruffy kid with glasses opens the door.
He looks at you, then he says, "Hi there. What's up?"
It's obvious he doesn't notice Pikachu. "Umm..." You point at Pikachu.
He looks toward where you're pointing, starts looking away, and then looks back at Pikachu, eyes wide.
"A-a-a...a Pikachu?!! Ww-what's it doin' here?!!"
"That's what I'd like to know," you say.
"But Pokemon aren't supposed to exist here, not...physically! It's gotta be a fake, or something!"
Pikachu looks a little annoyed, and it growls, "Pi-ka-CHU!" and shocks the two of you, feeling like a major static electricity jolt.
"How's that for proof?" you ask shakily.
"Good enough for me."
Both of you slump over, both looking very "shocked".
Pikachu crosses its arms, not looking annoyed anymore, and smiles. "Pikachu."
The two of you get up. "Well," the Pokemon genius says, finally getting a grip, "I can understand what Pikachu is saying, but I can't guarantee that I'll be able to help other than that." He adjusts his glasses.
"Okay," you reply.
The Pokemon kid kneels down toward Pikachu. "Why are you here, Pikachu? Tell us all the details."
"Pika, pika. Pikapika-ka, pika."
The kid tilts his head. "You came here by accident? What makes you say that?"
Pikachu sits down. "Pi, pikachu."
The genius smiles. "It's okay if it's long," he says, "we have all the time you need."
"Pika.
"Pikachu, pika, chu."
The Pokemon guy blinks. "You're Ash's pokemon?"
Are you surprised?
5
Yes, a lot6
No, not really