there is an unofficial kdice-wiki, in which you may find a loz of answers... this one for example:

What the hell is PHOENIX?
Who are the "lame" players who log in several tables, making useless attacks?
The PHOENIX contest is based on the legend of the phoenix bird, which burns fiercely and is reduced to ashes, from which a new, young phoenix arises. So the goal of Phoenix is to crash down your points until a really low rating and to rise up later as fast as you can. The best way of dealing with this type of players is to be prepared. The stats on every player's profile now show the rating at the end of each month and the maximum rating achieved during the month. So players that had high ratings (e.g. 2000+) and are currently rated very low are most likely phoenix contestants.