Nurgling
Nurglings are disgusting lesser daemons of Nurgle who are referred by worshipers of Nurgle with affection as 'Nurgle's little boils' and by everyone else as 'monsters', 'vile pusbags' and 'arrrrghh what the hell is that thing?!' Despite this, their models are alarmingly cute. They are born from the pustules and tumors that grow inside a Great Unclean One. Gross.
A Nurgling looks like a miniature version of Nurgle himself; a little bloated man shaped critter crawling with disease and hideous to look at, rarely reaching over a foot in height. They are spiteful, playful creatures, often demanding constant attention and picking fights with each other. The Great Unclean Ones laugh at the antics of the Nurglings and pat them with affection and shower them with gifts of scraps of meat. They do sometimes also have them as snacks though, not that this affects them, they just crawl out of some gaping wound or another. Other worshippers of Nurgle are not so forgiving of the Nurglings; the Plaguebearers see them as an awful nuisance, getting in the way and making jokes about the serious matters of life and death at hand, although they do secretly have a soft spot for them. Granted it's only soft because it's rotting, but it's soft all the same... I forgot where I was going with this...
Individually a Nurgling isn't physically powerful; it is the diseases that infest them that are the true threat. To let them touch you is to invite potentially lethal germs to infect you. It is in numbers they are truly dangerous though; Nurglings will often swarm underfoot and they can pull down far stronger foes when they attack en masse.
The best tactic to take on an individual Nurgle is to use a broom; against a swarm time to get out the old flamethrowers or the magic Lore of Fire.