This is the mother of the Larvitar Ash held on to temporarily. She appeared in Address Unown! in the dimension created by an Unown and Lavitar's memories. In the dimension, Tyranitar was seen fighting poachers, receiving a scar in the process, before Lavitar's egg was stolen by the poachers. She then appeared in Mother of All Battles. She mistakenly assumed Ash and friends were poachers until Larvitar calmed her down. But the poachers from Larvitar's memories appeared and capture Tyranitar.
After freeing herself from their clutches, she teamed up with Lavitar and blasted the poachers away with her Hyper Beam and Larvitar's Hidden Power. Soon after, she and Larvitar were reunited and bid goodbye to Ash and company.