Juggernaut.

Humanity is the dominant life form of this world. If you count it in destructive capabilities it is undebatable. We have killed so many other animal and plant species that we can easily be categorized as serial genocide maniacs. But I digress.

Humans are powerful for a few reasons.

The first: Advanced intellect, particularly planning and abstract thought.

Humans are capable communicating and thinking about things that don't exist, aren't literally happening and things that could potentially happen if certain courses are taken. As far as can be told, no other animal is capable of all of these things, and only a rare few are capable of just one or two. Frontal lobe bitches.

Anyway. The second thing is: Tool use.

Coupled with our first skill, this simple thing becomes highly powerful. It leads to technology and if anything will enable mankind to conquer the universe and discover it's mysteries, it is technological advances. Writing is only possible because of hands, and writing has lead to science, computers, mathematics, all kinds of things.

And the third: Cooperation.

Humans can, at least in part, work in a unified whole. One person can be as to nothing. An entire nation with a single goal are a powerful and terrible thing.

All these three things working in harmony to produce the horrible machine that is humanity, crushing all opposition in its wake. A bit melodramatic? Ask the dodo what it thinks.

In the bible, God stops humans from working in a cohesive whole when they attempt to construct "The Tower of Babel". The tower, though not as impressive as modern skyscrapers, is a symbol of humans' capabilities when our three skills work together totally unhindered. We could have become Gods ourselves before our time, when still weak in other aspects. And He says in the bible that "I, The LORD your God, Am A Jealous God" Meaning that he will tolerate the existence and worship of only one God. So God scatters humans and changes their languages from one to many, so they have arguments and do not work together in their entirety.

I have no doubt that humanity will eventually build space elevators and trans-dimensional travelling machines. And on the dark day that humanity finally defeats the limitations of its single star system and colonizes new ones, I will be rolling in my eons old grave.

I am both proud and ashamed of my species.