While very rare, upward lightning can occur immediately after a regular lightning strike near a tall object has already shifted the electrical field in the air. An electrical charge can then start in the tall object and move its way skyward.
Technically called a circumhorizontal arc, these aren’t rainbows at all. These happen when light passes through clouds at a high altitude, and a bright color spectrum forms between the many ice crystals in the cloud.
Also called a hole punch cloud or a skypunch, this awesome phenomenon gives the appearance of a giant hole missing from a cloud. This can occur when the water temperature in the clouds is below freezing but the water particles have not yet frozen. When the ice crystals finally form, they water droplets evaporate suddenly and in a domino effect, resulting in a missing hole.