Tierra is a character of the day who appeared in Control Freak!. She is an archaeologist trying to find a secret chamber in which a magical mask and staff, which had the power to control the minds of Pokémon, was supposedly located.

Brock's Golbat led the group to Tierra, who was found lying unconscious in her dig site. After recovering, Tierra invited the group to her site office, where she showed them the ancient tablet that had inspired her solo archaeological study. Meanwhile, Brock helped repair her equipment, and he upgraded her laptop to be compatible with Golbat's Supersonic waves. After learning that Tierra's digging machine had been destroyed, Brock also used his Geodude to Dig to the underground temple site.

However, Team Rocket had already reached the ancient temple first with their Dig-a-Tron. Tierra was shocked by Jessie's belligerence after she put on the mask and began to wield the scepter's power for her own purposes. Team Rocket reduced the underground temple to rubble during their escape in the mecha, though Tierra and the others emerged unscathed from the debris. After Team Rocket was blasted off by Pikachu, Tierra acquired the mask and staff to continue her research.