Taweret appears in the hippo form we're familiar with, but also as Reret, a sow (female pig) who eats demons. Yum. Her image is given as an amulet to pregnant women and children, to keep them safe from disease and nightmares and the dangers of birth.
Keeping a queen safe is important, especially when it's Queen Tiye, Amunhotep III's favorite wife. That's probably why he had golden images of Bes and Taweret put on the headboard of her bed, so they could watch her sleep. Isn't that cute? (Well, okay, in the dark maybe they scared the crap out of her… but he meant well?)
Taweret's image appears on a number of artifacts in King Tut's tomb, including a giant bed with hippo-head posts. Taweret's image showed up on lots of household furniture, like beds and couches, throughout Egyptian history. They thought her face would scare off nightmares and sickness just by being there.
Taweret starts appearing in tombs and temple reliefs as part of the constellation maps. She is called Nebet Akhet, or "Lady of the Horizon," and follows behind the Big Dipper in the night sky. The first depiction of Nebet Akhet is in KV15, the late New Kingdom tomb of Seti I.
Taweret shows up in the Book of the Dead, alongside her buddy Hathor, to make sure that dead people get to judgment safely. Lots of demons to keep at bay!
Tiny images of Taweret appear all over the place as necklace beads, figurines, lucky charms, and things buried with the dead. They're all to keep her attention—and protection—wherever they are placed. Some people carried the tiny hippos to guarantee pregnancy or keep already-pregnant women from having any complications. Others just wanted to feel safe: "Is that a hippo in your pocket, or are you afraid to see me?"
Taweret stayed popular even when the Romans took Egypt over. At the city of Oxyrhynchus, she had her own temple called the Thoerion, where priests and worshippers gathered for rituals and lectures and sometimes for dinner parties. The last known party for Taweret was held in 462. Weird fact: during this time, Taweret was sometimes considered an Egyptian form of Artemis. We have a hard time believing Artemis would want to be worshipped as a hippo, though.