Thanks everyone.
I didn't know if the spray can hair coloring would be good or not. I have never used it for our hair, but it is a plus that it is like hairspray too because I might not the hair to stand up some.
Does this stuff wash out good? I am sure it does since it is sold and used for Halloween costumes in human hair.
I have a big bucket of sidewalk chalk though, so that might be something...I am going to try that today to see what it looks like...I am just afraid it wouldn't be dark enough though.
And washable markers...that seems like a great idea...I have those too, so I might try some in a place that isn't too noticable right now.
THANKS AGAIN EVERYONE!!! You've been a big help!!!