I used to watch this cartoon when I was little, maybe around 2007, although I think it was older than that. I am not sure, but I think it was an anime. I do not remember it clearly but there was a boy and a girl who fought the bad guys. The boy and girl used to travel with the help of a giant robot or machine, they hopped on the legs of it. I think the robot looked like a cat (?) or some other animal. I've been searching on Google, but I can't find it with the little info I remember.