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.
How did you get in there spike?
Sometimes the shortest videos are pure win! Here's a video of a dog mowing the lawn.
This is what would happen if you bred Dobermans with Chihuahuas.
hmm, What's been going on at this park at night?