So alter self is not an illusion correct? It's a physical change? So if someone were to touch you, they wouldn't pass through pertruding features as with disguise self? Thanks in advance

That's correct. While not explicitly stated, since the spell is transmutation and not illusion, and the other two effects physically affect the caster, that's the most reasonable interpretation of the spell. Keep in mind the size & shape limitations, no changing amount of limbs and no stretching from a halfling to a human or vice versa. Have fun!

Thank you for the clarification

using this spell could create a "Venom" character, who uses Claws, Bite attacks.
could you also create the Tendril strike with it too? don't see range so likely not. But you could change your hands into Mace's and bludgeon someone too. Therefore have a kind of mimic type of effect with your body.
Being able to change the effect for the hour could be useful too. Breathing water, and still able to cast spells outside other concentration spells is useful too.
Could you give yourself Gecko like hands and feet allowing for a better climbing ability? What about eyes in back of your head?

Quote from MadPuppy57 >>

using this spell could create a "Venom" character, who uses Claws, Bite attacks.
could you also create the Tendril strike with it too? don't see range so likely not. But you could change your hands into Mace's and bludgeon someone too. Therefore have a kind of mimic type of effect with your body.
Being able to change the effect for the hour could be useful too. Breathing water, and still able to cast spells outside other concentration spells is useful too.
Could you give yourself Gecko like hands and feet allowing for a better climbing ability? What about eyes in back of your head?

I like the headspace you’re in.

Personally, I’d argue that gecko finger-pads, or some sort of climbing claws (claws being explicitly mentioned), would be completely reasonable (granting advantage on climb checks), while extra sensory organs would be a bit too far.

However, that’s completely between you and the GM.  It’s interesting to see creative interpretations of spells like this (Command spell also has this appeal).

Seems to largely mirror the ability of the Changeling race.  Although that race adds the restriction "You can’t duplicate the appearance of a creature you’ve never seen", which makes this more powerful, for simply a second level spell, albeit with concentration.

I take the statements "You can’t duplicate the appearance of a creature you’ve never seen [...]You decide what you look like, including your height, weight, facial features, the sound of your voice" as more or less a replacement for the Actor feat though, seeing as I decide how I sound, considering the changeling race says "Even to the most astute observers, your ruse is usually indiscernible. If you rouse suspicion, or if a wary creature suspects something is amiss, you have advantage on any Charisma (Deception) check you make to avoid detection".

But yeah, strong spell.

would wings be a reasonable ability for this?

I'd say no cause level 2 spells are a bit to early for flight. At the most maybe something to let you float down like feather fall.

Ya know. Why isn't this a Druid or Ranger spell? Even give it too the Bloodhunter. But this is a wizard spell? Makes zero sense.

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Quote from ThatsABigBagOfDice >>

Ya know. Why isn't this a Druid or Ranger spell? Even give it too the Bloodhunter. But this is a wizard spell? Makes zero sense.

It is for a circle of the moon druid and becomes basically a cantrip.

"Thousand Forms

By 14th level, you have learned to use magic to alter your physical form in more subtle ways. You can cast the alter self spell at will."

Quote from jb57542 >>

Quote from ThatsABigBagOfDice >>

Ya know. Why isn't this a Druid or Ranger spell? Even give it too the Bloodhunter. But this is a wizard spell? Makes zero sense.

 

It is for a circle of the moon druid and becomes basically a cantrip.

 

"Thousand Forms

By 14th level, you have learned to use magic to alter your physical form in more subtle ways. You can cast the alter self spell at will."

 At 14th level sure. But by then it kinda defeats the purpose especially as a second level spell. Warlocks even get it sooner.

Quote from ThatsABigBagOfDice >>

Ya know. Why isn't this a Druid or Ranger spell? Even give it too the Bloodhunter. But this is a wizard spell? Makes zero sense.

 Druids don't learn this spell because they all have access to their Wildshape feature. 

Rangers don't get access to this because it's not really supposed to be in their repertoire... The Ranger's role should be Scout, and they focus more on traversing and hunting, and if something comes up that the Alter Self spell could solve, the Ranger has "Beast Bond", "Animal Friendship" and "Conjure Animals" as alternate answers. Rangers have an appreciation for working along side nature, not replicating it.

I just facepalmed so hard.  It says, "You are proficient with your unarmed strikes."  By default, everyone is proficient with their unarmed strikes.  Still, this could be an interesting monk-wizard multi class, as it gives a +1 to unarmed strikes.

Playing as a battle smith artificer, is it possible to cast alter self on my steel defender, turning it into a suit of living armor I can enter to do battle in?

Quote from ZorgothTDK >>

Playing as a battle smith artificer, is it possible to cast alter self on my steel defender, turning it into a suit of living armor I can enter to do battle in?

 I think you can't, the range is "Self", so you cant cast it on anything/anyone but you. I checked the "Channel Magic" that Homunculus have (and wether the Steel Defender had that as well), but it only applies to spells with range "Touch"

RAW, the appearance change “doesn’t change your statistics”, so replacing your arms for wings would be purely cosmetic.

Would a character be able to change their gender with this spell? A player of mine wants to make a non-binary character and they were looking at spells that could change a person's body as a form of expression.

Quote from Okashido >>

Would a character be able to change their gender with this spell? A player of mine wants to make a non-binary character and they were looking at spells that could change a person's body as a form of expression.

 Gender isn't a physical trait, you don't need a magic spell to alter that. It doesn't specify changing sex, but it does specify "distinguishing characteristics", which one could argue that sex falls under. I'd say that's entirely up to DM interpretation.

Quote from Ozzie >>

Quote from Okashido >>

Would a character be able to change their gender with this spell? A player of mine wants to make a non-binary character and they were looking at spells that could change a person's body as a form of expression.

 Gender isn't a physical trait, you don't need a magic spell to alter that. It doesn't specify changing sex, but it does specify "distinguishing characteristics", which one could argue that sex falls under. I'd say that's entirely up to DM interpretation.

I would say yes with an asterisk. The changes are supposed to be purely cosmetic, so wings don't let you fly as others have mentioned, so I'd say any "parts" you produce are equally as cosmetic and unable to function if you're catching my drift. A big reason I consider it like this is that the Changeling race specifically lists sex as one of the things they can change, where as this doesn't.