But the real truth is that alien life on other planets could be even stranger than floating balloons or amorphous organisms ...

The Rock Pool Project in Plymouth says the non-native sea hare looks "alien-like".

The most beloved beings from strange new worlds.

These researchers captured photos that wouldn’t look out of place in an art gallery and used them to confirm new species of comb jellies never recorded in Colombia before.

More than 2,500 alien plant species could find suitable conditions in the Arctic, especially in northern Norway and Svalbard.