If your on a fiber/boosted server, just build a 2x2 metal behemoth gate filled with large bear traps. Then build a tower outside to shoot it with tranqs. Lead it in, it'll get stuck in the traps. After that, close the doors and go up your tower and tranqs it. They can't break metal so it's gonna be stuck.
I dare you to raise one!! They are savage if you got two high lvl parents (about lvl 140ish) and you get imprinting on it. The thing will become an adult with about 230% melee and basically one chomp any bronto!!! But on the down side you loose your job and your girlfriend
Make 4 metal dino gates and 1 large bear trap. Place three frames and door into an incomplete square and the large bear trap in the I between them. Lure the Giga into the trap and while its trapped place 4th down to make the square. Then just light it up with tranqs