Metal pig is a villainous pig that appears on angry birds tv and I believe it Mr. strange, he is an enemy of the body pig, he comes from Destroyer Island, like his enemy the body pig, he wants to kill the birds.
Before, as a child, the body pig lived on Destroyer Island, and he met Niumi, the real name of the metal pig, and saw a plaque that said:
Property of ?????? aka Mr. Strange, don't steal it.
Then after they got to know each other a bit, they became friends as the body pig gave him many gallons of gasoline and they became friends.
After they wanted to see more islands, they found Piggy Island and stayed there as they found an advertisement that was looking for a military general, the two went and did an exam and won the corporal pig, provoking the anger of Niumi and returned to its owner Mr. Strange and from there they became enemies.
Appearances on Angry birds tv:
-A metallic start
-Pig in sight
-The island of destruction (only appears as a memory)
-Do you know Mr. Strange?
-At the edge of everything
-The final battle
-Invasion 3000 part 1,2,3,4 and 5