What happens to "winter bugs" (冬蟲 동충)?

 ANSWER: They turn into "summer grass" (夏草 하초), which essentially means they turn into mushrooms.

In Korea, if a dead bee turns into a mushroom, it is called a 벌동충하초. If the larva of a silkworm turns into a mushroom, it is called a 번데기동충하초.

Cordyceps militaris in Arkansas | Mushroaming - Daniel Winkler's Webpages Dedicated to Mushrooms and Nature Tours