There are at least three different endings for the Gospel of Mark. Among these, the “longer ending” is the one that most people are familiar with, as this was found in Bibles until recently when translators began removing it or adding a footnote.
Today it is accepted by all biblical scholars that the “longer ending” is absent from the earliest copies of Mark, and only began appearing hundreds of years later. It is a later addition, not in the original. (1, 2)
However, that does not stop some people from creating a religion based on this “longer ending” of Mark. For example, it s only in this “longer ending” that we find the command to “pick up serpents” and indeed many people do: