I say LAZOR he is a hardcore one :p or My pikachu on my commentbox he is also Legendary Shut up you need first have a look to say sumthing to me about i think pikachu is a legendary pkmn :p
Anyways Here are My favourite:
1.Mewtwo (most likely robot form yep its one of the first series)
2.Darkrai
3.Ho-oH
And my Favourite pkmn is:
Gengar as child i loved things as skulls and ghost and other creepy things and Gengar was one of the funniest "scary/ghost" type :)