When my brothers were about 10 years old and 8 years old respectively they had been playing in my mother's room in a large cardboard box that they had turned into a fort. We were the kind of kids that could turn sofa cushions, bed sheets and a cardboard boxes into a mission control station worthy of nasa. This drove our mother crazy but our father thought it was cute so we got away with this on a regular basis.
That evening the hallway light had been turned off to "save" electricity, which is something my mother was famous for doing (and still does). My brothers were joking around and playing at being astronauts when suddenly I heard them both scream and duck for cover knocking over several things.
Being twelve whole years old I considered myself far too mature and sophisticated to play fort with my infant brothers so I had been reading in my bedroom on the other side of the hallway. I came into the room all authoritarian and asked them what was wrong and they said that they saw a "kangaroo" jumping down the hallway. I told them to stop playing around but they continued saying that they saw "a kangaroo" jumping down the hall looking like a shadow but definitely not a human shadow. I asked them it if could have been either of our dogs but they told me the "kangaroo" had been standing on its rear legs jumping down the hallway pausing once to "look at them" (How a shadow looks at you I don't know) and then continuing towards my room.
I never saw what they saw but they were adamant and refused to leave the hall light off ever again.