What the hell was Cameron Bancroft doing?

Bancroft used sticky yellow tape, which had debris from the pitch, while working on the ball in an illegal attempt to scuff it. To make matters worse, Bancroft attempted to hide the evidence when he realised umpires were suspicious. He stuffed the tape down his pants, instead showing umpires a piece of cloth in his pocket. Cameras captured it all and the match referee later charged him with ball tampering.