Creepy. This is definitely not for young children - too likely to induce nightmares and scare the shit out of them. But for adults this is a fun and well-done short animated horror film.
Parents tell their children all sorts of terrifying tales to break them of unwanted habits. When the monstrous mother of the young protagonist of Ben Tillett & Jake Cuddihy's Suckblood can't beat the thumbsucking habit out of her, she calls upon the vile creature who murders children who can't keep their fingers out of their mouths. Now the little girl must spend a terrified night without sucking her thumb for comfort.
This short is part of the Bloody Cuts anthology series of short horror films. This one has a dark fairytale feel and a gorgeous gothic sensibility to match. The tale even comes with its own grisly moral. Sweet dreams, thumbsuckers.