Small, angular UFOs or large, triangular aircraft are the second most reported UFO. When these types of craft fly near, they cause dogs to act strangely—eliciting fear, pain, or aggression. Diagonal ships often break off of triangular UFOs, and are much smaller; these crafts are silent, able to fly incredibly fast, move in pairs, trios, or large groups, and often take zigzagging or swooping paths. 

Diagonal ships are often a shiny black or darkly colored metal with one or two attached lights and/or tails in these colors: white, green, or blue; they are frequently mistaken for strange stars or comets. 

Triangular UFOs are giant, levitating crafts that are silver, gold, or dark in color with flashing, color-changing, or sometimes dim lights located on the tips or edges in these hues: blue, white, orange, and red. They often seem to move in slow motion. These aircraft fly at extremely high altitudes on nights with a full or half-moon; they tend to appear in groups of three or less, most often only accompanied by their smaller, diagonal counterparts. 

Many view these ships as signs of upcoming invasion; others see triangular UFOs as transporters for diamond crafts that may have business on Earth.