When I want to tame a carcha, I always use a baby rex because it always gives 100% trust, but i mostly find carchas in the cold biome on The Island, so its hard to incubate and hatch the eggs in the temperature of the biome, so I usually incubate it at home and get it at least 50% incubated, then use keys(usually 5)to hatch it, killing it and dragging it to the carcha.

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