Well, its sad when I think of all the possible Alien Races. Only one stands out as my Favorite.
They are big green of questionable intelligence. They are a combination of both animal, algae, and Fungus. They reproduce by getting killed in the height of Battle, their blood contains spores which will one day grow to be the next generation. They will grow larger and meaner their whole life until they are killed in Battle. They can build stars-ships, aircraft and other weapons of war. Only none of their technology should work, it is because they have a psychic like ability which empowers their technology. It also causes them to gather together for war under the banner of the Meanest and Largest member of their species.
They also have some funny traits, they love to get drunk, They have two Gods. one is who is brutally kunnin' and the other who is kunninly brutal they usually can not agree as two which is which.
They use teeth as currency, and since they regenerate teeth they can always take their own teeth.
They have several sub-species which grow from the same spore DNA, these are either smaller dummer little guys, two legged biting monsters, or giant pack animals.
Also the Color Red makes things go faster for them.
So can you guess who they are?
Race: Orks
Sci-fi universe: Warhammer 40,000 (WH40k)
Gods: Gork & Mork, or is it Mork & Gork?
Sub-Spieces: Gretchin (goblins), Squigs (nasty mouths on legs), Squiggoths (pack monsters)