There are several notes stating that "some manuscripts do not have" or "the earliest manuscripts do not have."
The end of the book of Mark is another place. Mark 16:9-20
Some argue that 16:8 was the last line.
Trembling and bewildered, the women went out and fled from the tomb. They said nothing to anyone, because they were afraid.
My study Bible states:
Serious doubt exists as to whether these verses belong to the Gospel of Mark. They are absent from important early manuscripts and disply certain peculiarities of vocabulary, style and theological content that are unlike the rest of Mark. His Gospel probably ended at 16:8, or its original ending has been lost.
This carries the part that brings some Christians to handle deadly snakes, although it doesn't really say deadly snakes.
Whoever believes and is baptized will be saved, but whoever does not believe will be condemned. And these sings will accompany those who believe: In my name they will drive out demons; they will speak in new tongues; they will pick up snakes with their hands; and when they drink deadly poison, it will not hurt them at all; they will place their hands on sick people, and they will get well."
"Peshat is what I say and derash is what you say." --Nehama Leibowitz
™ Version 4.2