Medium-sized physical-oriented undead with 12 RHD: I won't blame you if you stop reading here and skip right to the unsurprising end.
27 strength and 16 charisma are the only positive abilities, the others are nonexistent, average, or just plain bad. I'll admit that 6 intelligence is more than I expected, but it's still terrible.
Fast healing 10, unholy toughness, and +9 natural armor make the salt mummy quite bulky, but their only kind of offensive pressure is a 5 ft. reach, 2d6 slam. It's unclear if salt mummies can use weapons, with the art implying they can and the text remaining silent.
Dehydrating touch, the sole special attack of salt mummies, is not very impressive. 4d6 damage once a round is less than great, and the part where a fortitude save negates it makes it even worse (pop quiz: what save tends to be high on melee enemies?). It's also ineffective on constructs and undead, to make matters worse.
By the way, did I mention the part where water damages salt mummies? Y'know, just in case you still considered playing one.
Even something like the hill giant looks good next to this one. -0 LA, don't play this. The only interesting bit is that they're only 'often' chaotic evil, so idk, you can use a Good-aligned salt mummy as a surprise NPC sometimes or something.