So I'm using the terrifying goblins mod, and have the goblins set to terrifying. My fort is relatively isolated, so I dont get many immigrants. Which means my army is 4 legendary wrestler/adept swordsdwarves, all with light nervous injuries, and 2 legendary marksdwarves/wrestlers. I get about 6 goblin snatchers a season, and when terrifying, they are surprisingly hard to kill.
My solution so far is a minefield of cage traps, but that seems a little undwarvenly, mostly cause it doesn't involve magma. So I designed an Orbital Magma Cannon, cobbling together other designs ive seen. I still need to actually test it, and see what parts of it need to be magma-proofed, but here is the design for others who are interested in needlessly complicated ways for frying goblins.
Coded to improve readability
KEY:
M-magma Pipe
W-wall
F-Floor
D-Down Stair
U-Up Stair
X-Up/Down Stair
%>-Pump, arrow faces toward where the pump goes to
H-Hatch
A-Vertical Axel
^-Pressure plate, connected to hatch above
Floor 1:
MMWWWWWWWW
MM%> WWWWW
WWWWWWWWW
WWW
WUW
WWW
^ ^ ^ ^ ^
^ ^ ^ ^ ^
Floor 2:
WWWWWW
AW %> W
WWWWWW
WWW
WXW
WWW
Floor 3:
WWWWWW
AW %> W
WWWW W
WWWWWW W
WFFFWWWW
WFXFW
WFFFW
WWWWWWWWWWW
WHWHWHWHWHW
WWWWWWWWWWW
WHWHWHWHWHW
WWWWWWWWWWW
Floor 4:
WWWWWWWW
WFFF<% W
WFFFWWWW
WFFFWWWW
WWWWFFFWWWW
W W
W W
W W
WWWWWWWWWWW
All the pumps are Windmilled to produce a self-operated mechanism. This is only a small part of the design, which can be extended to easily cover the entire map, or outside borders.