You all make some good points. However, I think you guys need to dig a little deeper for this one. To me, it's clear that this comic is an intelligently constructed message, rife with religious metaphor. You see, Brad and his friend the dinosaur are currently living in purgatory.
As we know about purgatory, limbo, etc., it is a place to balance out and repay your sins of Earth so that you may be granted acceptance into heaven. Brad's frozenness depicts his attatchment to his former life on Earth, unable to move on to heaven due to his refusal to leave his sincs behind. Rather than simply have to carry his sins emotionally, he carries them physically as well, being frozen in place and unable to move. This is very telling of his situation, as he will not move onto heaven and will in fact be frozen in place in purgatory, so to speak, until he can leave his sins behind.
The dinosaur, however, is the opposite of Brad. His sins are washed away, happiness is his, and he is able to enjoy a smoke as he awaits his ascension into the world of God. Although, perhaps he is not going there. If one truly cannot shed their sins, their burdens become to heavy and they sink into the underworld, or hell. This seems more likely than heaven, given the dinosaur's talk of enticing Brad's mother to commit adultery.
By now we know, as readers, that the dinosaur represents what Brad will become if Brad does not change his ways. He will become a monster, and will be sent down to hell. Brad doesn't know this yet, but the dinosaur does, and is freely enjoying mocking Brad due to his inevitable fate.
The pasts of these characters are hazy. As the narrator inquires: "What could he have been doin with Brad's mom to be smoking afterwards?" Perhaps a rejection by Brad's mother cause the dinosaur to develop a smoking habit, or possibly cause him to turn to serious crimes? Intriguing.
But will Brad change his ways, rebuke his past crimes (whatever they may be) and move on to the City Of Heaven? Only future installments in this comic can give us the answer. More please, joo_joo!
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It's grime time.