A town in Siberia was shocked to see an ominous cloud lurking in the daytime sky, and many called emergency services reporting a UFO or mushroom cloud. Fears of nuclear war ran rampant on social media for a while before meteorologists explained the cloud as a natural phenomenon called an "anvil cloud," (cumulonimbus incus) which can occur during thunderstorms:
Similarly odd clouds have been reported in the world recently. TexasUFOs reported on a UFO-shaped cloud in Fort Worth that was witnessed right after a craft was seen shooting behind it. As well, photographs of a large UFO cloud in Colombia took the Internet by storm back in June, with most concluding it was just a Lenticular cloud formation.
Compare these photos of clouds to photos of a real Mushroom Cloud, triggered by a nuclear explosion (bomb). It is important to note that mushroom clouds can be caused by volcanic explosions as well:
What do you think this could was formed by? Natural weather? A nuclear explosion? Aliens?