Arjuna's Penance?

These events take place July 4th. We are in Mahabalipuram visiting Pallava sites

Arjuna's Penance is a huge bas-relief mural. It's about 100 feet long, maybe 20 high. It's the same pink granite monolithic style as the other sites. Like them, it's from the 7th century AD and made by the Pallava dynasties.
But what is it?
Well there are two interpretations. It's called Arjuna's penance. Here penance means something you do to get a boon or reward, not to make up for sins. Arjuna apparently performed an austerity to get a weapon from Shiva for the war with his half-brothers.

That would be Arjuna there, the old man holding a pose. I don't know this part of the story well, and I'm no art history scholar but if it was about him getting the weapon, where's Shiva and the big payday? Usually these are pretty literal.

Oh, but look: the kitty is doing the pose too! He wants the mice to think he's a guru and come over to worship him. Then wham-o! Dinner time.

And what about these critters? This is where the other interpretation comes in. See how this is a crack in the rock? There used to be water from above running through it here. This could be the Descent of the Ganges. We've seen earlier in the blog where the great river came down from heaven and was filtered through Shiva's hair. This would make the person doing the penance Bhagiratha. I don't know this story well, either, but apparently he did penance to have the river come wash away the ashes of his relatives.This seems a little more plausible to me. The creatures in the crack would be Shiva and Ganga then. But I don't know anything one way or another. To me it was another cool powerhouse scupture.
And there were more to come, we are only about halfway through. Stay tuned