These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Luckily, while they are fast and deadly, they can't take more damage than a regular troll, so enough focus fire can kill them quite quickly. Plus, you can avoid being picked up if you just keep on moving (so long as you don't move towards the Yeti).
A possible tactic might be to cast Charm on the yeti to pacify it first, then attack with your strongest spells. Charm is also thankfully easy to memorize, being W-E-D (Life-Shield-Rock).
Another useful tactic is to buy time with a cold stone wall (ERD), then use water to freeze them. Once they're all frozen, you have enough time to smash them with rock, then re-freeze them before they can move.
Or, you can just cast that rock shield (ED) onto yourself -ice if you prefer- to prevent them from picking you up without burning yourself. Even the lightest shield will do.
Dwarves are among the toughest Elite Mooks out there. They're as armored and tough as Orcs, they have Arcane resistance that severely diminishes the power of Arcane beams, and they can cast spells. Among these spells, they'll often use Teleport to avoid your mine traps or to box you in, and use Earth element spells to launch rocks at you that, if you don't have a shield or armor up, will One-Hit Kill you. Thankfully, they're also extremely slow, so it's not all that hard to keep your distance and hammer them from a distance, if you have the maneuvering room.
Malignant Beholders are also living nightmares. While they aren't nearly as fast as Yetis and can't take as much damage, they more than make up for it with massively damaging ranged attacks. Their lightning bolts can drain personal shields very quickly, and if you decide to drop your shield and go with lightning resistance, it'll use its main eye to insta-freeze you, then insta-gib you.
Goddamned Bats: Goblin archers. The arrows they shoot don't deal too much damage, but they do have this tendency to knock you down if you're using a shield. And by the time you get up, they have another one notched, ready to knock you flat on your ass again. And this is only with one; against multiple archers you may as well just lean back and let your wizard's shield drain. Gives a new meaning to Annoying Arrows.
This is even more telling in the Vietnam DLC, where firearms will knock you down, and unlike arrows, do not have a travel time, so having a personal shield up means you'll be spending more time on your back than actually casting spells. Which makes it a bit of Fridge Brilliance since you need friends to get anywhere.
Most Annoying Sound: Every time the Exposition Fairy speaks. Which is a lot. While it's supposed to be a parody of expository companions in games (Navi being the most obvious example), some people feel it worked a little TOO well and are compelled to kill themselves for the sole purpose of shutting her up.
That One Level: The Caverns Challenge map is arguably the hardest one available. The first basic thing that makes this level hard is that it's set on a very small platform that makes maneuvering very hard. Since it's set underground you can't use weather spells, Lightning Bolt, Summon Phoenix, or Napalm, which means that collecting those spells from treasure chests becomes useless. You also have to face waves upon waves of Dwarves, and Malignant Beholders. And to top it all off, the enemies will sometimes use the elevator in the center of the stage to attack, which means that if you're not careful you'll find yourself being attacked from all directions at once, including from below.
Unfortunate Implications: Magicka: Vietnam. The enemies are pretty much the same as in the normal game... meaning, you're Running around Vietnam, mowing down hordes of short, ugly, stupid, yellow-skinned goblins. Um...
On the other hand, real Vietnamese couldnt manhandly heavy machine guns like trolls.