a shapeshifting Alien that can turn her arms, legs, and etc into weapons like Axes, Hammers, etc, it was Odette from Metal Slug Attack!

Greetings, Earthling. My name is Odette, and I hail from the planet Venus. Please allow this alien to introduce herself. I am a skilled warrior who can morph my arms into deadly melee weapons. My skin is shaded in soft shades of green and white, and my attire consists of a tight-fitting suit that accentuates my slender feminine form. Let us engage in combat, Earthling. I will obliterate you!

she transforms one of her arms into a steel axe, you noticed that the limb is a bit, purple?