Any body suspended in space will remain suspended in space until made aware of its situation. A character steps off a cliff but remains in midair until looking down, then the familiar principle of 16 feet per second squared takes over.
A body passing through solid matter will leave a perforation conforming to its perimeter called the silhouette of passage.
The time required for an object to fall 20 stories is greater than or equal to the time it takes for whoever knocked it off the ledge to spiral down 20 flights to attempt to capture it unbroken. Such an object is inevitably priceless; the attempt to capture it, inevitably unsuccessful.
All principles of gravity are negated by fear.
Psychic forces are sufficient in most bodies for a shock to propel them directly away from the ground. A spooky noise or an adversary's signature sound will introduce motion upward, usually to the cradle of a chandelier, a treetop or the crest of a flagpole.
The feet of a running character or the wheels of a speeding auto need never touch the ground, ergo fleeing turns to flight.
As speed increases, objects can be in several places at once.
A painted tunnel entrance may or may not be traversable
Certain bodies can pass through a solid wall painted to resemble tunnel entrances; others cannot. ... Whoever paints an entrance on a wall's surface to trick an opponent will be unable to pursue him into this theoretical space. The painter is flattened against the wall when he attempts to follow into the painting. This is ultimately a problem of art, not science.
Any violent rearrangement of feline matter is impermanent. Cartoon cats can be sliced, splayed, accordion-pleated, spindled or disassembled, but they cannot be destroyed. After a few moments of blinking self-pity, they reinflate, elongate, snap back or solidify.
Everything falls faster than an anvil.