Source: Starfinder Adventure Path #2: Temple of the Twelve (Dead Suns 2 of 6) p.51

Level Mystic 1

School transmutation

Casting Time 1 standard action

Range personal

Duration 1 minute/level

Your mouth expands to twice its normal size,and fills with rows of razor-sharp teeth, giving you a bite attack. This attack is treated as an attack with a basic melee weapon with the operative special quality for purposes of proficiency and Weapon Specialization and for other abilities that function with basic melee operative weapons. You can make this attack without using any limbs and when pinned.
The attack deals 1d4 piercing damage. At 7th level, the damage increases to 2d4. At 10th level, it increases to 2d8. At 14th level, it increases to 3d8. At 16th level, it increases to 4d8. At 18th level, it increases to 5d8. At 20th level, it increases to 10d8.