One night, Tituba and some other girls are dancing around in the forest. To the untrained eye, it seems that they're engaged in some kind of weird pagan ritual. To the God-fearing folk of Salem, this is anathema, something strange and evil.
Reverend Parris is certainly of this opinion. When he comes across the girls cavorting in the forest, he's thoroughly scandalized by what he sees. To make matters worse, his own daughter Betty and his niece Abigail Williams are among the group. When Parris suddenly leaps out of the bushes, Betty is so shocked that she immediately faints. As well she might, because she knows just how much trouble she could be in now that her father's seen what she's been up to.
Parris is convinced that the girls were engaged in obscene practices, abominations, no less. But Abigail tries to assure her uncle that they were just playing games. Be that as it may, Parris is already thinking of what this might do to his reputation if it ever gets out. As he tells Abigail, if it transpired that the girls were trafficking with spirits, then his many enemies in the church will use it against him.
Parris is involved in a bitter political struggle with a rival faction in the local church, and he knows full well that his enemies would gladly weaponize the girls' weird cavortings and use them to drive Parris from his pulpit.