True Vore

You commit a sanctified ritual act of Voring another creature. When the spell is cast you choose a living creature within 5 ft of your choice. The creature is instantly prone while you are performing this spell, if it is performed as a ritual the creature must be prone for the entire duration. You occupy the creatures space if it is a medium or smaller creature. 

After you complete the spell you choose a ability score of the creature. The creature loses 4 in that score, this effects the base score and does not factor from increases by any other means such as magical items. You gain a 4 in any stat of your choice, up to a cap of 24 in a single ability score. This effect lasts until you complete this spell again on another creature, the creature keeps the -4 to that ability score and you retain the +4 to your ability score.

You can only retain one instance of the benefit to your ability score. If you cast this spell again you can choose to switch ability scores to add the bonus to or keep the same one.