Satan is the father of lies (John 8:44). Nowhere does this show up more than in how he pictures himself and his minions. Much of what people think they know about Satan and his demons comes not from Scripture but from sources like Hollywood and Medieval tradition. One of Satan's chief ploys is, of course, to convince us he does not exist. But the other false pictures can contribute to this by saying if we cannot believe in them, we cannot believe in him.
One of Satan's other strategies is to portray himself as more powerful than he actually is. This worked very effectively in the Middle Ages, producing great fear and ultimately encouraging people to lash out at those who were in some way painted as Satan's agents. Today in many forms of media we have the demonic shown as powerful, and good as marginal and barely competent. This need not involve direct reference to demons but to other powerful supernatural beings. It can end up making evil look empowering and liberating and good as hopeless. If Satan can even get well-intentioned people to feel overwhelmed and helpless, he has won a victory. But Scripture teaches he is a defeated foe (Colossians 2:15; 1 John 4:4), who should treated with caution but not cowered before (1 Peter 5:8,9; Ephesians 6:10-13).
His opposite move, though, is to picture himself in a crude, simplistic way--even a silly way. He becomes the guy in red tights with horns and a tail or the blatant huckster who forthrightly asks, "Want to sell your soul?" If this does not get people to dismiss the whole thing as silly, it presents evil as obvious and easily avoided. It also can cause people to see demonic forces as easily dealt with and their plans as easily foiled. Even the common idea (which has no basis in Scripture) that Satan and his minions are currently torturing the lost in hell can make it seem he is off the scene on earth. But Scripture pictures him as a clever schemer who can disguise himself and his followers as promoters of good (2 Corinthians 11:13-15; 2:11) and who is in control of this present world (2 Corinthians 4:4; Hebrews 2:14,15). We need to be careful of underestimating Satan, but should trust in God's power to deal with him (James 4:7). But we also need to avoid taking Satan's pictures of himself as the truth.