Bevendre

Because I was asked, and just in case anyone was curious as to the potency and situational magic in Raricow’s milk:

It causes changes if it is consumed before it has been able to ‘breathe’.  Ere go, if one were to drink straight from Rarity, or from vacuum sealed bottles (like the milk machine turns out) they will begin changing.  A full irreversible change would take place after consuming over a gallon.  It is difficult, but possible to do so accidentally as the milk is also highly addictive before breathing.