"Okay, okay," it said, blinking its bug-eyes at me, "don't act so surprised. MacDonald warned you, didn't he?"
"But—but—"
"Sure, I'm real," the monbeast volunteered, scratching its scaly head with a long-nailed finger. "That's the trouble with you guys. You're full of imagination, but you can't face reality."
"Where—where'd you come from?"
The monbeast shrugged massive green shoulders. "The whole thing's much too technical for me to worry about. All I know is us BEMs exist, and we get to your dimension via science-fiction."
"That 'power of mind' MacDonald was talking about?" I said, shuddering a bit.
"Something like that. Other forms of fiction deal with things native to your world. Science-fiction regards us BEMs as real, so while we don't ordinarily exist here, there's a stress created in the barrier between us, and we come through."
"Then you're really real?"
"Practically. Right now, though, you're the only one who can see and hear me. You haven't characterized me sufficiently so that the readers will be convinced that I'm real. But that's okay. You'll improve."
"Thanks. But now what about you?" I said, trying to not appear overanxious. "Are you returning to your own dimension or are you staying here for awhile?"