New trees + new undead with pulping+terrified dwarves.
So my current embark had something like 9 necromancer towers in the civ screen. Cool should be fun. Embark with a couple marksdwarves and train some hammer/axe dwarves in full iron armor and weaponry from the first 2 migrant waves. The undead show up, 4 undead goblins (a lasher,mace,axe, and bow goblin) and an undead elf. In 34.11, they would have been readily dispatched in seconds.
So I send in 9 dwarves in full iron with hammers and axes. 6 of them are terrified and rout. 3 get cut to pieces. Then the 6 find there courage and come back one by one, to be swiftly cut to pieces. Lovely. So I'm left with my 2 expert marksdwarves. They don't have a prayer in the open, but my map does have quite a few trees. I order a walkway constructed from the top of my guard tower to the nearest treetop, and send my marksdwarves across into the tree canopies. Sure enough they find a good firing position and start going to work. It takes them about a month to kill each undead using iron bolts, but kill each undead they do and 5 months later my map is clear of undead and I have 2 legendary marksdwarves.
So yeah, trees and undead.