Chameleon Christians are Christians who conform to the world. They sin as the world does and sometimes even believe as the world does (Morally). The Bible tells us
"And be not conformed to this world: but be transformed by the renewing of your mind, that you may prove what is that good, and acceptable, and perfect, will of God." -Romans 12:2
Right off with saying this is wrong, the Bible also gives a description of how these people may be.
"and he then begins to beat his fellow servants and to eat and drink with drunkards." -Matthew 24:49
Those aren't exactly meant to be taken particularly literal. The "Evil Servant" (Chameleon Christian) isn't exactly going to get drunk and beat or bully other Christians. They will sin as the world does, so lying, cussing, bullying, bad attitudes, sexual immorality, hatred, unforgiveness. You get the picture.