those black hole sandworm things that pull you in?
fuck them. you can't stop them from getting close because they travel under the ground, then when they're close enough they pop out and vacuum you in for like 7 seconds. and of course, Siren can't telekenisis them out of the ground so when you're caught, you just have to take it and hope you can finish it off and get a second wind. that shit is dumb.
also, who's bright idea was it to have an equipable shield that randomly ejects lightning grenade things upon taking damage...that can inadvertently damage you (and I mean big damage), depending on where their launcher falls? It's a high-value shield, but that shit killed me at least twice tonight just randomly popping out after taking damage when I was peeking out behind a corner. the lightning grenade thing would just bounce off the wall in front of me (or some other nearby object unbeknownst to me, zoomed in shooting people) and utterly annihilate me. I can't imagine why these should damage YOU. That mechanic actively discourages me from using the shield (which is probably my best shield, otherwise) because it's just too unpredictable. When it works right (when it lands near a medium-distance target or group of targets, that feature is really cool...but when it ends up right next to you...it helps the enemy more than you.