a description

Their ships are usually very weird; kind of like wrapped up technological nuclear shells, that do not fit in to the surrounding environment. You can compare it to the cars that we nowadays tend to use. So, in fact, it is quite easily recognizable, where this kind of developments could come from.

What was attempted, was that they wanted to use Earth as their portal to be accessible by these weird technological shells, and they still do (airports, cars, etc).

However, it can easily be seen how ridiculous and destructive these kind of attempts are, especially when they violate the very core law of mechanics: don’t build explosion-based things (engines).