Warning From Space (1956)

A group of starfish-like aliens from the planet Pyra, which is on the same orbital plane as Earth but on the opposite side of the Sun come to Earth to warn mankind about a runaway planetoid known as Planet R that is on a collision course with Earth. It is feared that when Earth is destroyed that their planet will be destroyed as well. However, their form causes people to panic, so they chose a female member of their race to take human form to spread their message. They then decide to contact a prominent scientist who has invented a new source of energy that can also be made into the most destructive bomb the world has known to destroy the planetoid. Unfortunately, the scientist is kidnapped by enemy agents who want to use the bomb for their own purposes. Now it becomes a race against time to find the scientist so he can complete his formula and save mankind.