Smurfing

From TribalWar

Smurfing, also known as fake-nicking, refers to when you use a nickname other than your own, in games or chats. The reasons for doing this are many, but the most common ones are: To fool opponents into underestimating your skills by using a nick noone heard of before, thereby scoring easy points and humiliating your opponent. To pose as another known player to be able to play competitively(against the rules) for teams other than your own. To be able to play or chat without influencing your reputation, e.g. when you're drunk. To avoid stalkers, especially ones who hunt after popular players