Big brain minecraft plugin that lets you sacrifice stuff to do things. Things get sacrificed on an altar that consists of a flat 3x3 of iron blocks with a gold block on top of them in the middle. Just throw things on the altar and right click the gold block.
New effects are really easy to add, just make a copy of BlankRitual.java inside of the rituals folder and then add in a combination of addIngredient(), addSacrifice() and other properties under setup(). Then write your own custom effect under execute(). Finally, go into the main class and register the ritual with the rest of the others.