These are the Forunner and Flood that appear in the Halo games and books.
About this creation
This is 343 Guilty Spark, the incredibly annoying monitor of installation 0-4. I don't know one person who did not hate this guy. He has an insanely annoying voice, plus he keeps laughing to himself oblivious to the fact that you are being swamped by thousands of flood as you move toward the index in the Library level. Then of course he turns evil and tries to kill Master Chief and all life in the galaxy. I hope Guilty Spark dies in Halo 3.
This is my Halo sentinel which I just made recently. I really like how it turned out. The blue dot is the sentinel's "eye," and the red/orange one is its beam weapon which you can pick up in Halo 2.
This is an Onyx sentinel from the book Halo: Ghosts of Onyx. I know that the three boom pieces are not actually suposed to be attached to the body, but in the book they just sort of float alongside the body which isn't really possible to do with legos.
Just like in the book, my Onyx sentinels can combine to form a double sentinel. As sentinels combine, their shield, propulsion, and weapon systems increase in power, making double sentinels very dangerous.
These are my flood combat forms. The middle and left ones are elite combat forms and the one on the right is a human combat form.
These are flood infection forms, mine are basically the same as Saber Scorpion's.