A cool puzzle

Mate in 1. You can promote into anything but a king.

No I didn’t 

Promote to witch.

Nope

Yep.

Although the witch cannot capture, the witch moves like a queen or knight, and can also jump two squares. It is transparent to friendly pieces, and makes neighbouring pieces transparent to friendly pieces.

So... 1. b8=W#

The rook delivers the discovered check, while the witch makes the rook transparent, so the queen guards the witch. The king is in check and has nowhere to go.

You said I can promote to anything but a king. I promote to witch.

No I mean a chess piece 

It's a bulldog chess piece.

There is no mate in one solution here.

I can't even find a mate in two, I'm there in three.

There is

Oh wait, I got two, it's easy, silly me.

There is mate in 1 mate in 2 and mate in 3

Ok well I'm

1. b8=N+ Kxb8

2. Qb6#

It doesn't matter what you promote to though, black is forced into 1... Kxb8 regardless.

There is mate in 1

Not possible to mate in 1.

No I said you can promote into anything but a king

Here is the answer: Promote to black knight 

Mate in 2 is easy. Mate in 1 is impossible. Only 2 queen moved and 4 pawn moves can put the king in check. None guards b8. So the king will live an extra move.

Oh