Continuity mistake: When Scuttle rips the seashell necklace from Vanessa's neck, the shattered pieces land at Ariel's feet, but a few seconds later they're gone.
Continuity mistake: When Ariel is taking a bath in Eric's castle and the women are washing her tarp thing, a pocket appears which later changes to a button.
Continuity mistake: When Sebastian follows Ariel into the grotto where Ariel keeps her human stuff, the door swings shut. When Ariel is going to the surface to look at the ship, the stone that closed the grotto has been moved out of the way magically. She just swims right out.
Continuity mistake: In the kitchen scene the chef pins down Sebastian with a fork, leaving two holes in the table. However, the holes are there before he does this.
Chosen answer: They are all throughout the film but the biggest one is when Eric is steering the ship to stab or skewer Ursula.
Disney-Freak