"We discovered a vertical hole on the moon," says JAXA's Junichi Haruyama. A mysterious tube so large and deep that it can shelter a future moon base. Until the creatures inside kill everyone, which is what happens in these cases.
Before, they didn't know what the hole's origin was. Now they have a theory: According to a study published in Geophysical Research Letters, the vertical cave—"213 feet (65 meters) across and some 262 to 289 feet deep (80-88 meters)"—may be a collapsed lava tube, which could provide a perfect shelter for a future moon base: