It's the flashy thing Gromit - and it's gone wrong! Russ and Molly have a moment of TV fame.
How do you hide the fact you're riding an East German concrete mixer? Hang a dog trailer off the back of it...
Despite no-one in this film noticing it at all, the motorbike here is a particularly heroic construction by my friend Russ, where an early '60s vee-twin air-cooled diesel was shoe-horned into a bike frame, Moto-Guzzi stylee. Which almost makes sense, when you compare it to his next bike, which is a VW Polo diesel mounted longitudinally.