Guild Wars 2

The very first time Toxx pops, get two players to intercept him and drag him off somewhere very, very slowly killing him.

Then everyone else builds siege, hires skritt, etc. You have only the one mob, Toxx, and all those building materials just waiting for you, and with Toxx off getting plinked to death, you’ll end up with a virtually impregnable fortress.

This is true, until (the next time) he/she spawns in the center of the map/circle. Had this happen already. It descimated about half of our defenses and killed on of the dolyaks (was on wave 6, or his third spawn?, I think).