1:

A “Gravity Hill” is a popular occurrence across California: a hill with a downward slope that, due to its surroundings, appears to be an upward slope. Because of this, cars are able to slowly roll down the hill and appear as though they are being pulled uphill. It has been said that at one such hill near Echo Mountain, if you cover the back of your car in powder and leave it for some amount of time and come back, you will find small childrens’ handprints left behind in the powder on your car.

2:

The informant began by talking about Echo Mountain and the lore surrounding it, of which much is distressing and and some is true. The Jet Propulsion Lab nearby had, she insisted she had confirmed, employed “some bigwig” who was also the leader of a satanic cult. Anything that follows, she acted as though was pure speculation.

In some of the camping trails in Altadena, the satanic cult which the bigwig led would meet and perform animal sacrifices. Somewhere nearby there was a mansion at the base of one of the Altadena Camping Trails which was supposedly the hose to local KKK meetings. It is near this mansion, “on the same street”, that the gravity hill is.

3:

A gravity hill on its own doesn’t require much explanation, as it is simply an optical illusion. The added element of “invisible children are pushing your car” is what interested me the most about this urban legend. I think the intention is to imply that the children are ghosts, which would line up with the number of uncomfortable stories floating around about the area in which the gravity hill can be found. This would be very easy to disprove, so I think it probably exists more as a joke which stemmed from the reputation of the area.