Movie with Aliens being sold on the Black Market

Question

I watched this movie when I was a kid, around 8-9 years ago (I think) and I can't remember the title or find it on google.

I seem to remember it being kind of a documentary style story shot in a desert area with Fallout looking huts and a market where Aliens were sold illegally. After eating them, humans would mutate or die.

The main character was (I think) forced to eat them but he evolved instead of dying. And I remember a kind of hospital later in the movie. The Aliens were tall with long legs.

Answer 1

You are probably remembering District 9 (2009).

From Wikipedia:

The film is partially presented in a found footage format by featuring fictional interviews, news footage, and video from surveillance cameras.

...

In 1982, a giant extraterrestrial spaceship arrives and hovers over the South African city of Johannesburg. An investigation team finds over a million malnourished aliens (derogatorily called "Prawns") inside, and the South African government relocates them into a camp called District 9. However, over the years it turns into a slum, and locals often complain that the aliens are filthy, ignorant lawbreakers who bleed resources from humans.

Following unrest between the aliens and locals, the government hires Multinational United (MNU), a huge weapons manufacturer, to relocate the aliens to a new camp outside the city. Piet Smit, an MNU executive, appoints his son-in-law, Wikus van de Merwe, to lead the relocation. Three aliens, Christopher Johnson, his young son CJ and his friend Paul, search a District 9 garbage dump for an alien fuel, which after twenty years Christopher finally has synthesized enough to enact his plan. But when Wikus comes to Paul's shack to serve him notice, Wikus finds the hidden liquid container and accidentally sprays some of it in his own face while confiscating it. Paul is executed by Koobus Venter, a cruel MNU mercenary.

Wikus begins mutating into an alien. He is taken to the brutal MNU lab, where researchers discover that his chimeric DNA grants him the ability to operate alien weaponry.

There is a scene in the movie that shows people killing and eating aliens them in an attempt to become aliens and use their weapons. As mentioned above, the main character slowly becomes an alien, not from eating them, but from accidentally spraying himself with a liquid from a container. The same people also attempt to eat the main character, as he achieved their goal of transforming into an alien.