Beyond the Grave
Monster Manual IV includes six new undead creatures, including the aforementioned web mummy. Undead tend to be a staple of many a D&D campaign, so do any of these look interesting for play? Well, yes. They do.
The Bloodhulk was first introduced as a D&D Miniature (the Bloodhulk Fighter from Deathknell), and then later used in Fantastic Locations: Fane of the Drow. It's nice to see the full creature entry. There are actually three bloodhulks presented here: medium, large and huge, and the Bloodhulk Fighter (CR 4), Bloodhulk Giant (CR 6) and Bloodhulk Crusher (CR 8).
I rather like the Bloodhulk. It's basically a big walking corpse, bloated with an infusion of the blood of innocent victims. There are two points about the Bloodhulk: they have lots of hit points (maximum on the dice), and they're fragile, taking more damage from slashing and piercing weapons. This gives them a very nice feel to them: their strength is also their weakness. They're not complicated, they just work.
The Defacer (CR 6) is a horrifying creature that steals the faces and souls of the creatures it slays. As far as creatures go in MMIV, it's one of the more complicated: it glides through the earth, it can spring attack, it stuns those it strikes, its stolen faces emit a frightful keening, and it steals faces when it slays a foe. Despite all of that, these aren't competing abilities but instead quite synergetic in their interaction.
One problem it does have is that its form of attack - spring attacking and retreating into the ground - could be quite frustrating, although the use of Ready Action would allow combat to properly occur. Defacers are created through the use of Create Undead on dopplegangers or similar shapechanging creatures - which has special significance on Eberron, as the entry notes.
The Necrosis Carnex (CR 3) follows the scheme of the flesh golem: its a bunch of limbs bound together and animated by dark (in this case, necromatic) magic. This is another creature where the designers had a lot of fun with its ability: its touch does negative damage (thus, healing undead), when slain it explodes in a burst of negative energy, and it takes additional damage from good-aligned weapons and spells. The logic from being a reservoir of negative energy to being more vulnerable to good attacks is lovely to see.
This is a creature that works as a healer for undead, and so they are used, especially in the Karrnathi military of Eberron. The three sample encounters make use of this.
The Plague Walker (CR 3) has a very disturbing picture - a bloated, shambolic form, dripping with pus. Once again, the designers gave this creature a weakness: Bloated Target, which means the penalty for firing into melee doesn't apply against this creature. Otherwise, the creature carries disease that infects those it strikes, and when badly damaged it can explode in a putrid burst that infects all around.
This last ability has a nice constraint on it: it's not a death throe. It has to actively will it, for a plague walker that dies before it can activate the ability just dissolves harmlessly.
The Vitreous Drinker (CR 11) is a servant of Vecna, and is very intelligent (18). For those unaware of what "vitreous" means, it's the gel that fills the eyeball between the lens and the retina. So, the Vitreous Drinker drinks eyes. There's something especially horrifying about that for me.
The Drinker has various spell-like abilities (arcane eye, eyebite, finger of death), the ability to steal people's ability to see, and a horrific gaze. Due to its high CR and special abilities, it works well as a spy or mastermind, although it's not a great melee combatant. I feel that there's something missing with the Vitreous Drinker - it uses its long tongue as a melee attack to damage and steal sight, but with only a +12/+7 attack bonus and not a touch attack, it seems a little too low for the ACs that are possessed by high-level PCs. Nice idea, but I really need to see it in play.