try searching the forums using the search functions. If you do so you learn that some players are able to shoot yellow phasers, pink disruptor bolts and so on. I even heard if you shoot a purple beam, a green phaser bank, a blue turret and a yello heavy cannon you can unlock the sith race
Might be a tetryon weapon. I'm pretty sure those have a blue coloring. You start getting them for yourself around Commander rank. Tetryon weapons have a side proc that cuts through shields too so that jives with your description.