Mutated Horrors plus Hi-Intensity Shock Troop Gauntlet Circumstance 
 Warhammer 40k: Darktide 

"Multiple enemy types have been imbued with foul warp energy, causing them to sprout tentacles. These enemies explode when shot in the head. Wyrmwood agents report increased Enemy concentration in the Mission Zone, as well as increased Specialist deployments. Expect Specialist strike teams."