Alter self into forms that don't have the same number of limbs

[Umbral Reaver]

Alter self lets you turn into humanoids. Merfolk are humanoids. Per the polymorph spell type, a spell that turns you into a humanoid doesn't meld your clothes and items except to change their size.

What happens to your pants when you get a fishy tail?

[HaraldKlak]

Umbral Reaver wrote:

Alter self lets you turn into humanoids. Merfolk are humanoids. Per the polymorph spell type, a spell that turns you into a humanoid doesn't meld your clothes and items except to change their size.

What happens to your pants when you get a fishy tail?

My suggestion would be to have them meld into the new form anyway. I'd reverse the logic in: " If your new form does not cause your equipment to meld into your form, the equipment resizes to match your new size." to rule that "if your equipment can resize to match your new size, it wil meld into your form".

Another solution would be to have them transform into the merfolk equivalent of pants.

Only suggestions though...

[James Risner]

Umbral Reaver wrote:

What happens to your pants when you get a fishy tail?

This is an "Ask your DM" question.

I'd rule they meld, but your hips up gear doesn't.