Popularized by the 2014 movie "Foxcatcher." An ungrateful ape is typically used to describe a degenerate, typically an individual who does not appreciate the blessings that are given to them. Also can be used to describe an individual of color- typically one who likes to wear trap clothes and look trashy. Most likely prioritizes things like purple drank, designer clothes, and hellcats over what really matters.
Person 1: "Look at that ungrateful ape over there"
Person 2: "Yea look at his ape ass, I heard he's 6 months later on Laquisha's child support payments."