How do you make a dog chase its tail around?

I saw an ad on TV today. It showed a dog chasing its tail over and over again, as dogs are wont to do, for about 45 seconds. It must've done so *atleast* 30 times in that time span.

And once it finished, the caption at the bottom was - "Comcast. Non Stop. 24/7/365". Not too bad you say? Perhaps, but commenting on the sad state of affairs that is the America Television Industry is not the topic for a short post.

Instead, it got me thinking about how such an ad would be implemented. Consider - you would need to find a dog which is known to chase its tail around. As an ad person, how would you approach this?

First thoughts include trying to find people who have talked about or perhaps written about their dogs' eccentricities. Hmm, but how often do you find people like that who live near you? Just finding a dog which doesn't look ugly as hell and is known to chase his tail for eons isn't enough. Although this by itself is a tough problem, once you DO find him - how do you make him do his thing? surely, you wouldn't be cruel enough to attach salami juice onto his tail and make him sniff it. and in case of a particularly stupid dog, even have him bite it. Its not unknown, after all.

I'm still trying to work this out. Next post is going to be a tag which STS gave me a couple of weeks ago!