What is a 번데기?

A 번데기 is the pupa-stage larva (애벌레) of

a silkworm (누에) in the process of metamorphosis to become

a silkmoth (누에나망).

 Many Koreans, and some naïve non-Koreans, eat 번데기, which is often collected after

the cocoon (고치) of the silkworm (누에)

is unwound and twisted into thicker silk thread (비단실).

The silk thread is then weaved into silk cloth (비단).

In the 1960s and 70s, Korea's 번데기 came mainly from Korea's big textile mills, but these days most of it is imported from China. I think Koreans started eating 번데기 because they were hungry, but now I think many eat it just to gross out friends and foreigners.