>>281440660
End of chapter. Here are two notes by Furinkan: "We see a paper lantern with one eye and a tongue hanging out. This is a chochin obake (提灯お化け), a haunted paper lantern. They appear often in ghost stories, prints and illustrations of haunted scenes.
Matsugo's laughter is written "kukukuku" (くくくく). This is considered to be "evil laughter"."

Furinkan also notes that this is a lot like the cursed caves in Ranma 1/2, but honestly, Rumiko did a similar plot in Urusei Yatsura too, so I think she just likes the device rather than it being a deliberate reference.