Field guide No. 434
Black flames in the snow
Burning, in negative.
In a snowy burnt-out forest of black trunks, one stump burns with tall black flames that give off no light. It’s the only warm thing for miles and it doesn’t look it.
Field noteFire is mostly light. Black flames with no glow are fire with the main feature taken out.
Also possible, also breaking physics
Muddy footprints through the skylightFootprints belong on floors. These cross the ceiling and keep walking on sky.
Paper migrationPaper can be folded into whales; it cannot then go flying. The obstacle is aerodynamics.
The patient needleSteel does not root. Biology has turned down this application several times.
Basalt balanced on a soap bubbleBubbles burst under a fingertip, let alone a ton of rock. Unlikely, though not self-contradicting.