ph34r the kut3 1s = fear the cute ones
b4k4 = baka = idiot
.md4 is a Quake 3 character skin file type
This is a remake/followup to b4k4.md3, which was used on the original b4k4^2 t-shirt in the now defunct MegaTokyo CafePress store with the heading "ph33r the cute ones".