I am playing in the Direwolf20 pack on Minecraft version 1.10 from "Feed the Beast," and just returned from the nether. At first I thought my game was bugged because I slept through the night but none of the mobs were dying they were just on fire, they also aggroed at me much more than normal. I also noticed slimes spawning where they shouldn't. After a moment I realized I was under the effect of "Curse."
What is this? Is this causing the mobs to be more hostile than normal and what causes the curse?
You can see the status to the left with the icon: