Text (VI+errata): 1/1. ; Whenever ~this~ becomes blocked, it deals 2 damage to each attacking creature and each blocking creature. [Oracle 2009/07/08]
If it is blocked by a Dream Fighter, the order of triggered abilities is used to figure out what happens. In this case, the Dream Fighter's phase-out ability resolves first. This is because the other player puts their triggered abilities on the stack after the current player does so. [D'Angelo 1999/07/10]