Is it possible to get an arceus to be a ? type?

Question

if so, how?

Answer 1

No not unless you hack

Answer 2

It's possible, but you can't use it with the type, so there isn't really a point.

Here's how it works (Gen IV)
1) Give arceus a sky plate and teach it roost.
2) Use Roost. Arceus will lose it's flying type for the turn.

Arceus will become a ??? Type in Gen IV and a Normal Type in Gen V if you do the two steps I just mentioned

Answer 3

That is impossible unless you hack.