These are mango worms similar to maggots, they feed on proteins in tissues found under the skin of dogs, cats, goats. Like Botfly's, they are transferred under the skin by mesquitoes that have come in contact with the eggs, they grow, manifest, and have to be removed or they could breed more thoroughly, as seen here.

HOLY SH*T!!! Make sure you didn't eat before watching this.

At least he keeps on playing.

This guy performs a field operation on a cow which has eaten so much plastic rubbish that it has become very sick. He saves the cow's life. Gross!

Hey when you gotta go you gotta go!

The loud music must have rattled his guts.

Moral of the story: Pick up your dog's poop.

Make sure you watch this video before you eat any food today or you might puke. Holy sh*t this is nasty!

That was mighty impressive.

This guy had an itch in his ear and couldn't figure out why.