Ex. This type of person will say or do something negative to you when you accomplish something great in life, simply because they want to put you down and hurt your self esteem or confidence. No one asked their opinion, they simply lash out negative verbal attacks or actions to put you down.
For lack of better words, I would say, "You're just a hater".
However, the word "hater" by its definition would not make sense in this statement. Let's say you could prove in court and to anyone that this person does not hate you at all. So if they're not a "hater" of you, what word would describe them?