To the people who suggested you use four metal gates and large bear trap, etc….no. nope. Absolutely not.

The bear trap only holds for a second and a half, and the giga climbed right over top of the walls like it was nothing. The best way to do it is to get shocking tranquilizing darts, a long neck rifle, and a griffin ( shoot the giga while on the griffin) and get the giga to follow you into a deep valley or ravine and shoot from the top of the ravine. (Ragnarok addition)