If ur playing mobile in solo, (lvl 150max), u need at least 200 tranq arrow (ascended bow) and hit him less than 5 seconds in every hit, 500 of narco, I discover 2 place that u can stuck him without take any damege the first one if he spawn at ice mountain just try to take him (take arge with a dino) giga will follow you, in the cascade at the middle of up of the map ( the highest cascade in the up) and try to make him stuck in the broken ice place, remember to stay in high, he can’t hit you.