One of the prettiest poisonous plants that I know is the Snowrose / Christmas Rose (Helleborus niger). That it blooms when everythingelse seems dead and or resting, has ever fascinated me. After reading up on it, I saw that I have the means to keep one happy, so I can grace my window now with one, too. Outdoors, of course, where such plants belong. In spring, I will get it a nice large pot for it to permanently live in.