Hi TC...
A Wacom tablet is a peripheral graphics 'drawing board' kind of tool.
It's considered the best of the best of it's type and is a valuable tool for use with artwork such as yours, and for computer artists, gui "skinners", and people like me who dabble in all the aforementioned.
Instead of a mouse, you use an electronic pen with this graphic's tablet. It allows for very precise control overy every aspect of your artwork.
....and speaking of artwork, I love what you've posted so far, and would like to see more! (lol, that lower one looks like my dad....)