Bitter melon is an oblong, wrinkly & warty textured, waxy-feeling vine fruit eaten primarily in southeast Asian cuisine. Its bitter flavor is considered an "acquired taste" to most Westerners and is strongly associated in Japan with Okinawan cuisine and with Okinawan longevity. It is one of the main ingredients of goya chanpuru.
It also happens to be pronounced "goya", which is the nickname of I-58 from Kantai Collection