Can you use Terapagos in its Normal Form?

Question

You know, the smaller one, it immediately changes its form when entering field, so, is there an way to stop the transformation?

Answer 1

Tera Shift cannot be copied by Trace, Power of Alchemy, or Receiver. Tera Shift cannot be replaced by Lingering Aroma, or suppressed by Neutralizing Gas.

As there is no way to suppress or change Terapagos' ability in or out of battle, Terapagos cannot be in its Normal Form while on the field through legitimate means. However, if you obtain a Terapagos with a different ability through hacking, it can battle in its Normal Form.

Source

Additionally, Yamask isn't available in SV, though if it was, Mummy and Wandering Spirit likely wouldn't work either.