[Monsters] I am a Doppelganger ... of a Demon?

[Incenjucar]

For an "angel" doppelganger I'd probably just let them slither on their angel tail.

 

[Kordeth]

For an "angel" doppelganger I'd probably just let them slither on their angel tail.

Oh, just let it drift around like an actual angel not using its fly speed. Why not? It's not like floating gives him any special advantage or ability.

 

[Cabral]

As it stands, the only Doppelganger we've seen in the NPC version.

When we get a full playable Doppelganger race write-up, either online, or in the 4ECS, I'm confident that they'll spell things out a little better.

The playable Doppelganger race is at the back of the Monster Manual.

It allows the doppelganger to look like any Medium humanoid, with no change to anything else at all.

I more concerned with the silliness some of the forms provide, particularly those with origins other than natural.

A doppleganger doesn't become insubstantial or gain any other powers of its new form when it changes shape. If it changed to a ghost, it would look like a ghost but would be quite solid (giving it away). If it changed into a zombie, it would still breath (probably giving it away). If it changed into a legless angel, it would have no means of movement.

Why is this a problem?

As I mention above (in this post), mostly silliness, though you could argue that appearing as an Astral Stalker ought to give you a bonus to intimidate...

By the way, a zombie is an animate, not a humanoid. Would you say that a Doppelganger impersonating a ghost would appear as the ghost did in life, but perhaps covered in flour?

 

[The Little Raven]

Would you say that a Doppelganger impersonating a ghost would appear as the ghost did in life, but perhaps covered in flour?

No, it would appear as a slightly transparent, humanoid shape... like a ghost. It just isn't insubstantial, nor can it phase through objects, nor is it actually an undead creature. It just looks like it. Purely cosmetic. Total non-issue.

 

[Kordeth]

The playable Doppelganger race is at the back of the Monster Manual.

Several of the monsters in the Monster Manual have racial
traits and powers, not unlike the races presented in the Player’s Handbook. In general, these traits and powers are provided to help Dungeon Masters create nonplayer characters (NPCs). This information can also be used as guidelines for creating player character (PC) versions of these creatures, within reason. Note that these traits and powers are more in line with monster powers than with player character powers.

Like Mort said, we don't have a full playable write-up of the doppelganger as a PC race yet.

I more concerned with the silliness some of the forms provide, particularly those with origins other than natural.

As I mention above (in this post), mostly silliness, though you could argue that appearing as an Astral Stalker ought to give you a bonus to intimidate...

By the way, a zombie is an animate, not a humanoid. Would you say that a Doppelganger impersonating a ghost would appear as the ghost did in life, but perhaps covered in flour?

So, wait a minute--you're concerned about "silliness," but you suggest that a doppelganger turn into a person covered in flower or a flopping-about angel that can't move under its own power? Are you familiar with the old robot expression "DOES NOT COMPUTE?"

Seriously, all the silliness* goes away when you accept that the doppelganger is a magical shapeshifter that can look like anything humanoid and Medium sized without any problems.

* Except the silliness that a doppelganger can look like a ghost but not a zombie, that is.

 

[lukelightning]

If it changed to a ghost, it would look like a ghost but would be quite solid (giving it away).

With a fun bonus! Because doppelgangers can't morph their clothing, to look like a ghost it would have to strip. Nekkid doppelghosts!