In this case, the cost is to pay one mana and sacrifice a creature
Rare also tends to have more of the splashy cycles than mythic rare (as the bar for using up five mythic rare slots is high)
That is rare for me as I am very particular about the art I like
Haldan, Avid Arcanist + Pako, Arcane Retriever Haldan, Avid Arcanist and his dog Pako, Arcane Retriever are a fun Temur-aligned partner pair with a steal your opponents' stuff theme
Deal damage to an opponent, and you get to spin the wheel and see what nifty nonland card from the top of their deck you get to cast by paying life equal to its mana cost
In other words, for an extra two mana, you can play any creature you want, depending on the state of the game and the mana that you have access to