The Bio Rifle, known as the GES Bio Rifle, also known as the goop gun, is a staple of the Unreal franchise. The primary firing mechanism has been held constant through all the Unreal games; the gun shoots out small blobs of caustic green goop which explodes upon impact and sticks to whatever surface it lands on otherwise. The secondary fire, however, has changed in each addition of the Unreal franchise. In the original Unreal, the secondary fire button allowed you to store additional quantities of goop while depressing the secondary fire button. When the secondary fire button would released all the stored goo would be hurled out in one large blob, most often rewarding an instant kill to the weilder if contacted and if not it would stick to whatever surface it contacted. in Unreal Tournament, Unreal Tournament 2003 and Unreal Tournament 2004, the charged blob would split apart when impacting a surface spreading smaller blobs around the area of impact. Unreal Tournament 3 has reverted to the original 'giant blob' dynamic. The Bio Rifle is famous for being an instrument of suicides. It is very easy for your goo trap to backfire. Also if a charged blast connects with an enemy which is too close, that too can harm and kill you. The bio rifle can be used as a defensive weapon. One can leave a trail of goop behind them to deter a pursuing opponent.