What I've learned from battling these to find an R-Reaper:

1. As you've probably read, they project a spotlight passively, if you find yourself within this cone of light, prepare for a fight.

2. THEY HAVE A SHIELD. Save your ammo/element, their shield only comes down for approximately 1-3 shots of a tek rifle, or one shot of a shotgun. If working with another player time your shots & shoot together.

3. It's either summons or spikes! They will shoot a round of spikes at you OR they will shoot a slow moving purple ball down towards the ground, causing dinos to spawn. Unless the spawns are fliers just ignore them, stay in the air, and continue the fight.

IMPORTANT NOTE: The shield will stay up until it finishes the attack or finishes spawning in dinos, stay on the move until then!

Good luck and stay vigilant my friends