Last year I took a horse blanket and attached plastic flowers all over it, turning my horse into a flower garden.  Then I dressed as a bumble bee.  Not nearly as elaborate as the above pics, but it was quick and simple.

Hubby was not as inventive.  He and his horse both wore red bandanas over their faces and went as masked bandits

We rode to the local ballpark where they were having "trunk or treat".  We filled our saddle bags with candy to hand out.  The kids got a kick out of it.

Wish I could find the pics.

that is awsome! 

I can't imagine what it takes to put these together, much less the time and training it took for these ponies to put up with it without freaking out.

If I tried that with my mare, our theme would have to be "dead horse".

HA!

I think I could get a costume on my horses, but I don't think that they would stand around with all the other costumes floating by.  We'd be the runaway costume. 

The kids wanted to go as the wizzard of OZ last year with our dogs (fawn mastiffs) as the lions but I couldn't find a lions mane that I liked.  Saw a picture of a dog wearing one that looked real but there was no info on the picture to say where it came from.

We have dressed the pony in a full elephant costume and the kids were a monkey and a jungle woman(if it was cold weather,she was a safari person) I covered a water foam noodle for the trunk. Another idea is penguins and an iceburg.  One year a kid bubble wrapped his horse and carried a sign "No Winstar yet".