The Straw Golem is a Golem added by Thaumcraft 4.
You have discovered the secret of creating golem workers. While the Iron Golem is impressive in its own way, it is very limited and uncontrollable. You have managed to solve both those problems.
Your golem workers have just enough will and self-awareness to make them useful tools, but not enough to render them uncontrollable.
You have also discovered how to make the Golemancer's Bell and Golem Animation Cores (see their respective research entries for more detail).
The golem you craft can be placed in the world, but will remain inactive until given an animation core.
The placement of the golem needs to be considered carefully - if you wish it to interact with inventories, you will need to place it by clicking (or shift-clicking) on the inventory on the side you wish it to interact with.
Most golems can operate in a range of 16 blocks around their home location.
The first golem you can create is made from bundles of hay and straw. It is physically weak and easy to destroy, but very light and nimble.