It's a bit hard to assess from the photos, but it looks like the coin has been acid treated and likely was altered.
I don't know of any 1936 Philadelphia partial or missing third feather varieties. While there is a known 1936-D three-and-a-half-leg variety, this coin isn't close in appearance.
Grease Filled Dies sometimes can mimic missing feathers and legs and more, but I've never seen any coin with part of the buffalo's face missing due to grease, especially on such a sharp angle. The face isn't a commonly clashed area and generally isn't polished. The lone exception is the 1937-D three-leg variety, where one side of the beard was abraded, but even there the buffalo's face wasn't affected. Die polishing frequently removes the hair on the buffalo's head, but rarely abrades more. The only other common heavy abrasions are on the buffalo's back, close to EPU, which can be partly abraded when the dies are polished to remove the chin/EPU clash.
It looks as though the buffalo's face has been removed and two of the legs may have been altered. Scrape marks are visible on the top of the buffalo's right rear leg, and there is what looks like an acid interaction in the space between the buffalo's head and UNITED. None of that looks like any of the known three-leg or three-and-a-half-leg varieties. The third feather is still visible, which on a known feather variety coin would make it a two-and-a-half feather variety, rather than a true two-feather variety.
Again, it is hard to make the call from photos, but the appearance of the coin strongly suggests that the surfaces have been exposed to acid. The circle on the reverse is from a
Coin Wrapping Machine.