Conjure the one

You light the candles in a citcle and then you put one candle in the middle. Then you pour the blood. If you pour diffrent blood, diffrent effect ocurs:

Dragon: you grow wings and get a breath weapon aprropriate to the type of a dragon you got the blood from.

Behir: You get lightning resistance and darkvision. You also get the breth weapon.

Wyvern: You produce poison instead of saliva. You are immune to poison and the poisoned condition. 

Hobgoblin: You can naturaly find poisonus plants and use them to make poison. You also have advantage on death saves.

Halfling: You become small and can cast one spell of level 7 or lower once without expending a spell slot.