9 Movie Heroes & Villains That Didn't Know Each Other Existed
7. Billy Peltzer & Brain Gremlin - Gremlins 2: The New Batch
Though the Gremlins franchise's human protagonist, Billy Peltzer (Zach Galligan), is certainly well aware of the gremlins as a whole, he never actually comes into contact with the bonkers sequel's ultimate Big Bad - the Brain Gremlin (Tony Randall).
After Gizmo (Howie Mandell) kills the spider-gremlin Mohawk, the Brain Gremlin becomes the gremlins' leader for the rest of the movie, though neither Billy nor Gizmo are privy to this information.
They just know they've got to stop the gremlins, and that they do by soaking them and then siccing the electricity gremlin on them, causing them all to melt, including the Brain Gremlin.
And to the same token, prior to the Brain Gremlin's death, Billy and Gizmo are absolutely non-entities to him, as he's clearly more interested in the bigger-picture aspect - namely discussing gremlin-human relations.
While Billy might've learned about the Brain Gremlin after the fact given that he gets interviewed on TV shortly before his demise, within the movie itself they don't directly cross paths even while being in close proximity.