So anyway, hopefully you've all read the Harry Potter novels, more specifically Harry Potter and the Prisoner of Azkaban, where the Patronus Charm first appears. For those of you who haven't, here is the description from the Harry Potter Wiki:
A Patronus Charm is an insubstantial animal protector created by the advanced Patronus Charm spell, and one way to defend against Dementors and certain other Dark creatures. The spell requires the use of a wand, concentration on a powerfully happy memory, and the incantation "Expecto Patronum".

A Patronus that is fully formed, or corporeal, takes the shape of fairly solid-looking animal; a non-corporeal Patronus appears only as wisps of silvery mist. It is a very complex charm and many qualified wizards and witches have trouble with it. Harry Potter is one of the youngest known wizards to cast a Patronus. The Patronus Charm, like Animagus forms, has been said to reflect the personality or feelings of the witch or wizard. They are, however, subject to change if the caster goes through an emotional upheaval of some sort.
Anyway, before I go on any longer about the awesomeness that is All Things Harry Potter the point of this post is: what kind of animal do you think your patronus (assuming it manifested itself as fully corporeal) would show up as?
Lydia, being both a doctor and a clever writer, argued first that hers would be a Paramecium, then she selected a Kiwi (the bird, not the fruit) for a moment before finally settling on a Platypus.
My own Patronus would manifest itself as a Mountain Lion, also known as a Cougar, I'm quite confident. How do I know this, you ask? Because as a teenager I went on a Vision Quest, and discovered that the Mountain Lion is my Spirit-Animal.
I fully realize that may sound crazy, but I'm not joking.
More on Vision Quests and Spirit-Animals next week (although if you name your Patronus Animal in the comments, I promise to break down what that would mean as your Spirit Animal, in another post).