Find one with gene scanner.

Defeat it once.

Get the altar from its corpse.

Place altar in good place away from base but near it.

Use giga and place it over the altar.

It will ask for any of the tributes for the center or scorched.

You can miss 3 tributes, the altar will break on the fourth missed tribute.

Kill the Dreadmare after every successful tribute.

If you miss a tribute you must fight the missed tribute animal along with the Dreadmare.

If you fail to defeat the missed tribute animal it will result it efficiency loss.