Heretic/HeXen: MF_Ripper Blood
In the original Heretic and HeXen (i.e powered the up Dragon Claw or Mages wand) individual blood splats caused by missiles with MF_Ripper would only very very occasionally be launched in the direction of the projectile. The rest of the time, it would fall to the ground.
In Beta6.3, every blood splat spawned is thrust every time. 1.8.6 mimiced the original games behaviour with regards to this flag.