Top 5 most annoying mob-skills

Everytime I level a new alt, or run through some old instance/raid content with my mains, I run across some mob-skills that are insanely annoying. I thought I'd share them with you, so you get a heads up at what to avoid like the plague (pun intended). These skills all have two things in common - they're all used by mobs in vanilla WoW and they all prevent you from doing what you want to do in some way. Back in the days, Blizzard seemed to take some special pleasure in designing skills that by themselves could kill an entire party and that often needed a special party setup to be countered. In their defence, many of these skills are used by mobs in instances that once were considered raid instances. And we all know raid instances are supposed to be tricky. I always dislike any kind of mob skills that continously and actively prevents a class from doing their job however. A stunned tank can't tank anything and a silenced healer can't heal anything.

5 - Stuns
There are some mobs in places such as UBRS, ZG and EPL that have a 2 sec stun (in ZG it's even a ranged axe toss stun), which seems to have a very short cooldown. If you run in these areas with the hopes of clearing the area quickly at level 80 you might very well end up dead, simply because you're stunlocked to death, very very slowly. This has happened to me a couple of times. At 80, if you're geared enough you might live it through, especially if you're some kind of class which does damage to your opponent even when stunned, like paladin retri aura, prot warrior damage shields or druids thorns. Any other class will definitely have to beware however.

4 - Add summon
The mobs that summon adds can be found at quite different places, but they're all very annoying. My first encounter with this type of mob were the Swarmer Scorpids in Barrens. If you happen to play a class which doesn't have some kind of counter-dmg aura or aoe, and by that level very few classes do, you'll have a hell of a time killing those little shits. The second room in Scholomance can easily turn into a sea of skeletons if you don't kill the summoners fast enough. Their summon skill has a 2 sec cast and they won't stop casting it until they die. In the old days you needed some really careful pulling and fast nuking to counteract these kind of mobs. In this setting it is ok, since they are part of the event. But when having to face these kind of mobs on your own, playng a class which has no counter measure for it except killing them one by one (rogues for instance), this can be a real nuisance. Fortunately they have buffed lowbie aoe quite alot, like giving priests holy nova at 20 and reducing spell interrupts to a maximum of twice per cast, which make these kind of mob skills slightly easier to handle nowadays.

3 - Charge Knock
This is quite similar to the stun, but adds a fly back knock to the effect. A knock that might have you pull more mobs, which happens quite often in instances like UBRS (the dragon guards that knock you down into the whelp room for instance). At other occassions this knock will just simply kill you, like with the stun you'll be stunlocked to death without being able to do much about it. This is the case with the Crimson Courier pack of mobs in EPL. The Crimson Guards in the scarlet area of Stratholme are another example of mobs with charge knocks. They can charge the healer enough to effectively prevent them from healing anything. What's even more annoying about these charge knocks and stuns are that they seem to be completely free of level restrictions. It doesn't matter if you're level 60 or 80, you'll be stunned just as much. Diminishing returns? Forget it. I'm not sure if this can be countered by standing close, like with the Titanium Vanguards in HoL. My guess would be no.

2 - Cadaver Worms
The Mangled Cadavers in Stratholme have a disease that used to be extremely annoying. So annoying in fact that you needed someone to cleanse it to be able to do the instance at all back in vanilla. And still at 80 it could really prevent the advancements of any class not being able to cleanse it. The disease is Cadaver Worms. I just read, when doing research for this post, that they had nerfed it. I used to be 10 minutes long, reduce your health regeneration with 100% and inflict 150 shadow damage every 10 seconds. That means your hp would slowly go down, and the only thing you could do against it was bandage or heal. The regular out of combat hp regen would not take place, and the eating of food would do nothing either. To be able to bandage you had to time the 8 sec bandage channeling perfectly between the two dot ticks.
Like I said, they've nerfed it (or buffed, depending on how you look at it) now to a 30 second debuff that reduces health regeneration by 50% and inflicts 150 shadow damage every 10 seconds. This is a significant nerf and this disease isn't much of a nuisance anymore. It used to be extremely annoying however, and I suppose the mere fact that Blizzard has decided to change it eventhough no one really does Stratholme except with their level 80 mains anylonger, verifies this.

1 - Enveloping Web
Yes, the very most annoying mob skill (that I can think of) is yet another skill from Stratholme. Back in the days this instance, which was a 10-man raid originally, needed alot of skilled people to complete. The baron run, which meant doing it in 45 minutes, was a real challenge. People were screaming for priest healers back then because of our abilities to dispel, cleanse and shackle undeads, which were really handy in that instance.
There is one mob in there that still drives me monkey-banana-crazy whenever I encounter it and that is the Crypt Crawler and its skill Enveloping Web. Enveloping Web, which is an instant cast so you can't interrupt it, will trap you (immobilize), increase the time between your attacks by 100% AND silence you for 8 seconds. Hah, take that! Imagine dealing with that back at level 60. It really renders the target nearly useless. As a tank, which usually is the target of this skill, you won't be able to do anything until the dps has nuked the mob down. If you happen to boost someone or even worse, do it yourself, you have to wait for the few seconds between the debuffs uptime (because the damn mob reapplies it almost instantly) to make some damage. Since the mob will move away from you when it has trapped you, you can't hit it. Since you're silenced you can't shoot it with spells. You're best shot at this is if you're a hunter who isn't bothered much by range or silences and can have a pet attacking the mob meanwhile.
Just thinking about this skill makes me angry <.<

Bubblers - Skills that are annoying but didn't quite make the list

The Scorpid Reavers in Shimmering Flats have a poison that ticks every 3 seconds for some minutes, making it completely impossible for a rogue to stealth or for any class (except shamans and druids) to bandage during the time. Very annoying.

Any mob with a fear is usually extremely annoying. The first mob that comes to mind are the bats of EPL. This isn't game-breakingly annoying like the ones in the list however, so you just have to suck it up and handle it! The same goes for any mobs with skills that...

- Heal themselves for all their hp when they're at 3% and just about to die.

- Bubble themselves. Damn paladins are annoying even when they're npcs!

- Gives you a curse that reduces all your attributes by X% since that feels worse the better gear you have.

Have you got some own experiences with annoying mob skills?