You were running away from death(XMuffet and XMettaton.) In (AU of choice) they were destroying it killing everyone on sight. You saw that they were a monochromey type colour. You were terrified as you hid behind a tree, you soon faint from stress. You were later carried by someone as you awoken up to see XGaster

XGaster: Oh you are finally awake. My assistant will help you with injuries you are having. he exits the room leaving you with XAlphys

XAlphys: you’re going to be a problem..