My latest creation in Blender is a model recreation of the Robot Devil character from Futurama, directly based on the image shown below:
Once I had finished creating my model, I set to work creating an armature in Blender to rig to my 3D model, or – to put more simply – a "skeleton" for my creation that would allow me to pose it. Without any rigging, the base Robot Devil model looks even more frightening:

After rigging my character up with an armature, I was able to pose them into various positions. By making several key poses along an animation timeline (known as "keyframes"), I'm able to produce an animation where the character transitions between the multiple poses. The results of the poses are the GIFs shown at the top of the post – "idling", "waving", and "walking".

The "idle" pose was the first one I created, and it really shows; the movement is quite jank and doesn't quite look like what I was intending (I was intending for the pose to look like a 2D fighting game idle pose). The "wave" pose is quite smooth, but the frozen pose of the majority of the model is quite jarring, and makes it look so un-lifelike. The "walk" pose is quite nice, but it looks quite "robotic" (ironic!); the "robotic" look could probably be solved by adding more keyframes to make the whole animation appear smoother.