Fear
None of the actors were used to acting in front of “nothing” so they were shown pictures of what Arnold Vosloo would look like in fully Mummy get-up. This was meant to inspire fear.
Changing Direction
After The Mummy: Tomb of the Dragon Emperor was released in 2008, a sequel was in the works. The Mummy: Rise of the Aztec would see Fraser, Bello, Hannah, and Ford all reprising their roles and Antonio Banderas was going to play the villain. However, the film was ultimately cancelled and Universal Pictures instead chose to release a reboot in 2017. This would be the first installment in the Dark Universe franchise.