Sahih Muslim | Book 26 | Hadith Number 5558

Narrated by Asma' b. 'Ubaid
Asma' b. 'Ubaid reported about a person who was called as-Sa'ib having said: We visited Abu Sa'id Khudri. When we had been sitting (with him) we heard a stir under his bed. When we looked we found a big snake, the rest of the hadith is the same. And in this Allah's Messenger (may peace be upon him) is reported to have said: Verily in these houses there live aged (snakes), so when you see one of them, make life hard for it for three days, and if it goes away (well and good), otherwise kill it for (in that case) it would be a non-believer. And he (the Holy Prophet) said (to his Companions): Go and bury your companion (who had died by the snake bite).