Hi there, This is quite easy task and I'm 100% ready to make a background animation of a big dog walking down a street with a small dog running in the opposite direction like running away while dialing a cell phone exactly as you demand. I've almost 6 years of experience in Animation videos, After effects, Adobe Flash, Video services, Graphic designing & Photoshop and I'm sure you'll be 100% satisfied with my work guaranteed.
Also if you have any further specifications, you can surely contact me. I'm waiting for your positive response!
Thanks,
Usman H