Is this a prank or abuse?

J

A man secretly gives his vegan girlfriend milk to prove a point.

I dont know how she didnt notice tbh, I haven't had dairy in eight yrs and just the smell would get me, even more so the taste.

I dont think it was just a prank, as he actually harmed her and technically poisoned her.

What do you think?

Prank, abusive, or just a terrible boyfriend?