This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Kafka on the Shore
The scene with Nakata and the cat killer, Johnnie Walker, which might qualify as a Big Lipped Alligator Moment as what transpired is never mentioned in detail again.
Actually, though the event itself is not mentioned again, Johnnie Walker appears again toward the end of the novel in the mini-chapter The Boy Named Crow. He has apparently completed his flute made of cat souls, and Crow is helpless to stop him no matter how horribly he can disfigure the "man", because he's already dead. "Johnnie Walker" may possibly have been the evil worm-being trying to get into the Entrance Stone. It might not qualify as a BLAM, but it's still bizarre.
In addition, the event has some bearing on the other plotline involving Kafka.
AND Nakata admits to Hoshino that he killed Johnnie Walker.
The scene with the "worm-creature" is enough to send chills down anyone's spine.