Is there a way to make a perfect body double?

Question

Say someone was playing 5e and walking through a forest, and wanted to plan an ambush. Could that player, say they were a Dragonborn wizard, potentially make a "body double" of themselves, and then polymorph into someone, or something, else to wait in secrecy?

For Instance:

Dragonborn polymorphs into a deer, waits in forest appearing to eat grass as a deer would, goblin team walks down the road, notices the "dead body" in the middle of the road. Goblin party begins to loot dead body, Polymorph ends, FIREBALL!!! No more Goblin Party...

Depending on the answers to this question I will have another!

Answer 1

Clone creates a tangible body

The wizard necromancy spell Clone can create a perfect duplicate of a living medium creature given 120 days.

This spell grows an inert duplicate of a living, Medium creature as a safeguard against death. This clone forms inside a sealed vessel and grows to full size and maturity after 120 days...

The clone is physically identical to the original...

This could provide you with a body double one of two ways.

The first option is to remove the clone from its sarcophagus, dress it in appropriate gear, and replicate fatal wounds. Since the clone was never alive there might be some revealing details (ie its wounds would not bleed in the same way as a living person). If you needed the clone to walk you could cast Animate Objects. This would only work for 1 minute, however, before needing to be recast.

The alternative option is to create the clone and then arrange for your own death. You could then use your original body as the duplicate. If you need the double to be able to walk then you could cast Animate Dead to turn it into a Zombie.
This same general strategy could also be achieved with the spell Reincarnate as it can revive you while leaving your corpse behind. You would need to find a helpful Druid, however, and you wouldn't retain your original shape.

Answer 2

There are plenty of illusion spells that would handle this use case.

Mislead is pretty much directly on point for your description, if they can cast 5th-level spells:

You become invisible at the same time that an illusory double of you appears where you are standing. The double lasts for the duration, but the invisibility ends if you attack or cast a spell.

You could simply have the double lie perfectly still, as though it were dead.

If they can't cast 5th-level spells, Silent Image would work for the "create a double" bit:

You create the image of an object, a creature, or some other visible phenomenon that is no larger than a 15-foot cube. The image appears at a spot within range and lasts for the [10-minute] duration. The image is purely visual; it isn't accompanied by sound, smell, or other sensory effects.

The Minor Illusion cantrip would also work similarly, but only up to a 5-foot cube (fine, it can be curled up if needed) and only for 1 minute, which may not be long enough.

The illusions would be broken once they interact with the "body," but at that point, the fireball is on its way...