PFR

PFR, or Plasma, Frag, Rocket, is the act of throwing a plasma grenade, frag, then shooting a rocket each direcly after the one before it in Halo: CE and Halo 2. You can use this to send yourself, another player, or a vehicle flying. This is also used to send the player or vehicle through a wall or ceiling.

In order to do this you need an overshield. In Halo 2, this can be harder to do since the time to throw a grenade after another is longer than in Halo: CE.

There are several ledges and places you can get to by doing this. In Blood Gulch for example, if you do this with 400% shielding on, you can reach the top of the cliff pillar near blue base.