Bill Murray and Arava the disabled tortoise. Photo: AP/Jose Sanchez, Reuters/Ronen Zvulu

Over the past year Pixar have tackled the role of the critic (in Ratatouille) and the end of the world (in WALL-E). Now they face their biggest challenge yet - a freewheeling creature feature played out in the badlands of Rio de Janeiro. It’s a hip and violent favela flick where the kids carry handguns and a hard shell is no match for a speeding bullet. This thing practically writes itself.

OK, fair disclosure. Today’s Casting the News is actually a conflation of two different news items - thematically linked but separated by the trifling passage of, ooh, a mere six years. First up we have the heartwarming tale of Arava, a female tortoise at the “Jerusalem Biblical Zoo” (so much better than that Darwinian Safari down the road).

The bad news: Arava suffers from paralysis in her hind legs. The good news: this week she reportedly “found love” after being fitted with a pair of back wheels. “Her new mobility had apparently made her a moving target for an amorous male,” cooed The Australian newspaper. Wow. She must think she’s died and gone to heaven.

So yes, we could simply limit ourselves to the Arava story. But that feels a little cloying and cutesy (perhaps even a trifle distressing as well, given the presence of that lumbering “amorous male”). Alternatively we could mate this item with the antique story of an unnamed male tortoise, caught in the crossfire of a Rio turf war and later rebuilt in a Steve Austin-style: augmented with a pair of back wheels that were sawn off a TV cabinet and strapped on with sticky tape.

I’m pitching this as The Tortoise and the Hare meets City of God. It’s about an innocent pet that falls foul of a gangster rodent but then gets his revenge courtesy of a bionic makeover. I’m suggesting Bill Murray to voice the tortoise, and Jim Carrey to do the hare. But we also need someone to play the “poor owner” who loves the tortoise but can’t afford to take it to the vets (Alan Arkin, maybe). And if we’re going to bring in the Biblical Zoo angle we obviously need an amorous suitor to eventually “find love” with. I nominate Zooey Deschanel, if only because she took a similar slot in that cartoon about the surfing birds.

Now as you can see I’ve flipped the gender roles and taken a mainstream, Hollywood route. You might want to take a more exotic path. Your version of the tortoise tale might be a Hayao Miyazaki animation, or a Jan Švankmajer puppet show. The casting is even more of a free-for-all. Seeing as their aren’t many actors who bear an obvious resemblance to a paralysed Brazilian tortoise, you’re pretty much free to pick whoever you like.

Here’s what we need ...

The Tortoise

The Hare

The Poor Owner

The Tortoise Girlfriend/Boyfriend

The title

The director/studio

Thanks for your responses to last week’s Olympic divers biopic. Where to begin? Were going with bengaliman’s suggestion of Nick Berry to play testy Blake Aldridge and (just to up the absurdity levels) dazzabrimma’s choice of Peter Kay to play precocious, fresh-faced Tom Daly. Dexterities’ tagline (“as easy as falling off a log”) likewise gets the greenlight. And for the supporting role of Lin Miaoke, the duplicitous little minx who thought she could get away with miming to someone else’s voice? Ah, greatpoochini, if only it were true. Do you really think we could get Tom Cruise to sign?