The stream is located in Biržai district, the village of Likėnai. The well pit consists of a very flat bottom-like collapse into an oval funnel. Its diameters are 15 and 17 m. Water flows to the Smardonė stream from heated layers of sedimentary rocks. It is bitter to drink, has a faint unpleasant hydrogen sulfide gas and smells like a bad egg, which gave it its name. The first studies of the stream water were carried out in 1816. The results were published by electrochemist T. Grotthuss. In the past, the stream water was used for therapeutic purposes, but is not used today.