Vypper is a creature of the swamps, haunting them, fighting for the territory with the kikimore.
| I looked for the words "Witcher urgently needed". And then there'd be a sacred site, a dungeon, necropolis or ruins, forest ravine or grotto hidden in the mountains, full of bones and stinking carcasses. Some creatures which lived to kill, out of hunger, for pleasure, or invoked by some sick will. A manticore, wyvern, fogler, aeschna, ilyocoris, chimera, leshy, vampire, ghoul, graveir, were-wolf, giant scorpion, striga, black annis, kikimora, vypper... so many I've killed.
— page 116, The Last Wish (UK edition)
Vyppers are large reptiles, like vipers the size of alligators. They can stretch their jaws wide, but the fangs are not as much of a threat as they look. It is their poison one should beware of.
- Vyppers are mentioned in the passing in the short story A Grain of Truth.