netherwart cows

So the nether uptade seems pretty cool but i have a new mob idea that will spawn only in the nether dimension and especially in the soul sand valley   it is the netherwart cow it is similar whith the brown moshroom cow but its body is going to be made out of soul sand and there will be netherwart growing on it's back.

now  let's talk about it's usefullness  so if you feed it for example a golden carrot , some netherwart  and then use a water botlle on it it will give you a potion of night vision but to make it fair you will need the double amount of resources.

for example when you are using a brewing stand yu will ned only one golden carrot to make a night vision potion. 

but when you use the netherwart cow  you will need two golden carrots.

so that was my idea i hope that it will get enough votes for it to get implemented in the actual game.