Pokemon Trivia 3?

[Xzuby]

The hardest one yet, I am sure!

I am a Pokemon that evolves into two different kinds.
One of them has three types, the other type has one.
There is a certain item you must use to find me.

What are the names of all three Pokemon, the types of them, and which item is required?

First correct answer gets 10 points.
Well, Wraith, I was going to specify... but YOU GOT IT RIGHT! I will make your answer Best Answer as soon as I can, but I cannot at the moment as the question was posted too recently.
Yeah, what I meant by three types was the Pokemon could have three different forms. Like Wormadam!