Just wondering do the natural weapon use the spell casting modifier, dexterity modifier or strength modifier

Quote from Dynaco4 >>

Just wondering do the natural weapon use the spell casting modifier, dexterity modifier or strength modifier

The rule seems to state that attacks with the natural weapon are unarmed strikes. Thus, you would add your strength modifier to the attack roll, as normal.

i would argue it is dependent on your DM.
a sonic the hedgehog type spinner w/spines i would base on dex with slashing damage.

This is going to be a dumb question? But can Alter Self turn me into metal (specifically for my hands/feet as natural weapons)

It doesn't  specify but does this change just your form or does it include what you are wearing. Limits the disguise value if you are wearing the same clothes. Since it's shape-shifting rather than illusion I would assume it doesn't affect. You're. Equipment 

If aquatic adaption is a thing, I don't see why aerial adaption wouldn't be. Why can wings be grown?

P.S. It only says STATS don't change. (Strength, Wisdom, Dexterity, etc.) But I would make an argument for wings being allowed to fly or maybe just glide.

Or maybe the DM could make the decision of, "Hey you've never had wings before and you don't know how to use them. Make a Strength (Athletics) or Dexterity (Acrobatics) check to see if you can fly."

My character already has wings but what the heck I just wanna know how I can use this.

Quote from Kazamaraz >>

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.

 if you really were interested in such a character, play a changeling

I'd completely allow it. Even have the physical changes permanent and functional thereafter if they wanted. Magic is magical, and tweaking an existing spell is easier than trying to homebrew a gender change spell. 

Quote from ArtificeMeal >>

Quote from Kazamaraz >>

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.

 if you really were interested in such a character, play a changeling

 Why should we force players into a race? I'd let them use the spell like this, and if cast often enough the changes are permanent and functional, if that's the desired result.

Could I use this to create long spikes sticking out of my skin all around my body? And if so, is there a limit to how big I can make the spikes? 

This spell makes me chuckle because I can't help but think of an old FooFighters music video where he grows his hand real big.

Would this allow to change a character's gender?, from a female to male or vice versa? Genuinely curious

Quote from Layomayo >>

Would this allow to change a character's gender?, from a female to male or vice versa? Genuinely curious

 This was already asked and there were discussions above. Up to DM but shouldn't be an issue.

The 3.5 version of this spell did allow you to grow wings for flight. They nerfed in in 5e just because I guess they wanted Fly at level 3 to be more special? I mean, that does affect a target and not just self, so it's still more powerful.

Since it historically was a part of the spell, you can talk to your DM about allowing it, but that really could go either way.

I'm curious about this line of Change Appearance: [...]your basic shape stays the same[...], how would that work on an Aarakocra, for example? In the sense, if it needs to pass as a creature of another race, could it also "dismiss" the wings while you turn yourself into a human, elf, orc, or some other wingless medium race?

I see this being more of a survival thing like darwinism. If you are stuck in water you need to breath and move from predators. You don't need to fly to survive in air but some way of safely falling like a flying squirrel could be feasible or even the way spiders hang glide.

Can I turn my hands into crab claws.

So...I have dumb question.  It says that you cannot change the number of limbs you have using the 'Change Appearance' option.  Would a tail count for this?  For example, if you wanted to change into a Tabazi, Lizardfolk, or Tabaxi, could you do that?  Additionally, if you could, would it be reasonable for this to grant any sort of mechanical advantage (say on Dexterity based checks)?

I think that yes you should be able to make a tale even make it into a natural weapon as it says. but I don't think that you should get a bonus for your tail because it says your stats don't change