I'm a big fan of the Ninja Pig spell so I came up with this idea, there could be this Ninja Pig trainer(looks like the pet you get with the gift card.) that would be placed some were in Mushoo and could teach you the Myth Ninja Pig spell, that along with all the other Ninja Pig spells.
, I got another idea there could be Ninja Pig spells for, Fire(Ninja Pigs wearing red and orange), Ice(Ninja Pigs wearing blue and white), Storm(Ninja Pigs wearing purple and yellow), and, Life(Ninja Pigs wearing brown and green).