A young boy tried his best to keep his pants from slipping down as he danced, fully focused on his traditional performance despite the struggle.

The co-founder of the Universal Store clothing chain has allegedly been stabbed to death by a teenage boy, who police say was known to him, during an after-school party at his Brisbane ­mansion.

The boy pulled out a machete, hidden in his pants, in response and threatened staff and shoppers before the pair fled the scene.