As Harry begins his sixth year at Hogwarts, he discovers an old book marked as 'Property of the Half-Blood Prince', and begins to learn more about Lord Voldemort's dark past.
This movie contains 34 potentially triggering events.
A significant one happens in the scene where Harry and Dumbledore go to retrieve a horcrux in a cave by the sea. There is a silence when Harry goes to get water from the lake itself and then there is a jumpscare, as he gets grabbed by lake creatures. That one in particular is really jarring.
Not exactly because a character looks like they are seeing things and pleading for someone or something to have mercy, to forgive him and to spare harry.