I'd like to see mechanics turn into grease monkeys, but that needs to wait until dwarven gears require lubrication.
Damn, that's a good subject for thinking about material spatters.
I have one fort with an extensive power network across multiple Z-levels. Suppose some clumsy mechanic spills a lot of grease around a gear that transfers power downward. That could present a slipping hazard, causing dwarves to plummet down the power shaft to their deaths.
And if they get the grease all over themselves, they could then track it all over staircases and near wells. I'd want to build waterfalls in all of the entrances to my utility system, and/or be careful to use dwarves with good agility or personality traits favoring cleanliness as mechanics.
And, like everything, it could have wonderful military applications. Besides the obvious pouring of boiling oil onto invaders or nobles, I'd want to build a system to pour grease onto my bridges, causing passers-by to lose their footing and fall into the moat to die.
Pouring water onto a bridge in freezing weather should accomplish the same thing. There could be a lot of other implications of water coverings turning into ice coverings when it's cold; long before someone gets encased in enough ice to be hilariously killed and used to decorate your fort, they should slow down from the ice layer accumulating on the joints of their clothing, and get icicles in their beards.
Hm. Weather is just rain and snow right now; how about some freezing rain? Besides the wonderful ice coverings, it could take down trees and kill saplings. Trees felled by weather should probably become auto-forbidden logs so that dwarves don't rush out into the foul weather to collect them.
On a totally different note, perhaps dwarves who spend a lot of time in sand, especially collecting it, should suffer the indignity of getting sand inside their clothes.