At the Highlands on Ragnarok, if you see a giga, try luring it into a cave at the river where there is a small pond. You can lure the giga inside it and it will be trapped. From there, just pump it with tranq arrows. Alternatively, you can shrink the size of the pond by putting stone gates so the giga can't move much. After you're done, just cryo the tamed giga or build a ramp so it can climb out

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