What movements teach the opposite of Christianity?

Answer 1

There is no real opposite.

Some religions or People have diffenent ideas in some Points of faith or reject some Points or the whole Christian Religion. But this is not a Religion it means heretic.

There are two forms of Satanism, the first smaller Group are really Follower of Satan, the bigger Group are People who criticize the structure of the catholoc Religion and it´s institutions.

Answer 2

I don't think such a thing exists. You can have "opposites" with simple properties, such as "big is the opposite of small". Christianity, on the other hand, is a complex belief system; you can have movements that teach the opposite in very specific points, but they would probably agree on others.