AFeldspar

So, I want to make a custom potion effect that is similar to strength and haste, but you die if it ends. I want this potion to be craftable in a crafting table and not brewable (I already added the crafting recipe, but no idea about the second part). I also want to make another potion that removes this specific effect ONLY when drank, and you don't die. I don't know how to go about making the potions or potion effects though, because everything I find is outdated.