We killed a Yuan-ti. Now we want to infiltrate their base disguised as one of the Yuan-ti we killed.

The PHB Page 211, Alter Self spell states:

You assume a different form. When you cast the spell, choose one of the following options, the effects of which last for the duration of the spell. While the spell lasts, you can end one option as an action to gain the benefits of a different one.

Change Appearance. You transform your appearance. You decide what you look like, including your height, weight, facial features, sound of your voice, hair length, coloration, and distinguishing characteristics, if any. You can make yourself appear as a member of another race, though none of your statistics change. You also can't appear as a creature of a different size than you, and your basic shape stays the same; if you're bipedal, you can't use this spell to become quadrupedal, for instance. At any time for the duration of the spell, you can use your action to change your appearance in this way again.

One would assume that Yuan-ti's are a "different" form due to the snake torso.

Disguise Self is also too limited. Polymorph only covers beasts.

What can be done if, as a wizard, you are trying to disguise yourself as a particular Yuan-ti you met on an adventure (that is now dead)?

  • 1
    \$\begingroup\$ What level is the wizard? Also was this a Yuan-ti pureblood? \$\endgroup\$ Commented Feb 28, 2018 at 14:36
  • \$\begingroup\$ The easiest solution is probably, kill another yuan'ti without snake body \$\endgroup\$
    – findusl
    Commented Sep 17, 2020 at 8:18

2 Answers 2


Since you specified a snake torso on the yuan-ti, it cannot be a pureblood and is most likely a malison. Alter Self will not work as you indicated, which leaves the following lower level options for disguise:

  1. Major Image (3rd level): A possible magical means is to use the Major Image spell to create an illusion of the slain yuan-ti, either using it to cover the wizard or moving it separately. It covers a 20 foot cube and can create the illusion of a Large or Medium creature. This is not the best option as the spell only lasts 10 minutes, requiring recasts or risk having it run out at the least opportune moment.

  2. Silent Image (1st level): This would also do the same, but is a lot worse as it doesn't cover sounds, smells, etc. It covers a 15 foot cube and can create the illusion of a Large or Medium creature.

A combination of the two spells, Silent Image for moving past other yuan-ti at a large distance and Major Image for closer inspections might do, making the best use of a wizard's limited spell slots.

Of course, higher level spells can do exactly what you need.

  1. True Polymorph (9th level) or Shapechange (9th level): The perfect disguise spells, but they require a high level caster (suggested by Dale M).

Alternately, while not exactly a disguise as you specified, this spell might also help you infiltrate the yuan-ti base:

  1. Animate Dead (3rd level): Raising the dead yuan-ti as a fresh zombie would serve your purpose well enough as an infiltrator drone. A yuan-ti malison is a Medium creature, which fits the spell requirements, a fresh corpse shouldn't create a rotting zombie and might pass as a living creature (requires DM ruling), control lasts 24 hours, and best of all it is not a concentration spell, which means the wizard can tag along while covered in Invisibility.

Edit: As mentioned in the comment below, Animate Dead requires humanoids and does not work with a malison which is a medium monstrosity, though it does work with a pureblood yuan-ti which is humanoid.

  • 1
    \$\begingroup\$ -1 Animate Dead requires a humanoid, a yuan-ti malison is a monstrosity. \$\endgroup\$
    – T.J.L.
    Commented Jun 27, 2020 at 16:13
  • 2
    \$\begingroup\$ If its the snake-head malison, why couldn't they use alter self? Its still a bipedal, two-armed, single-headed (humanoid) shape. The creature they're attempting to replicate might not be type-Humanoid, but it's shape is still reminiscent of the basic human form. \$\endgroup\$
    – Aaron
    Commented Sep 17, 2020 at 8:01

Depending on the type of yuan-ti, it might be possible. Alter self only stipulates that your size and basic shape are unchanged, and that you don't gain any statistical changes from this new appearance.

From pg 309 of Monster Manual, there are 3 types of Yuan-ti Malison

  • Type 1: Human body with snake head

  • Type 2: Human head and body with snakes for arms

  • Type 3: Human head and upper body with a serpentine lower body instead of legs

For Alter Self, Type 1 is viable. Type 2 could be questionable due to the 'snakes for arms,' thing. Type 3 is unsuitable.

As stated above, there are other viable options, and you could always get creative with constructing a clever disguise that incorporates magic and mundane structures, (or you could pull some Weekend at Bernie's shenanigans)


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