This mecha paper model is Emerald Princess, first appears in "Prisoners of Love", when she is kidnapped by Ice King, based on the American animated television series Adventure Time, the papercraft is created by WebDude.
Emerald Princess also appears in "Loyalty to the King," where she is one of the princesses who wants to meet the Nice King (Ice King). Emerald Princess is one of the princesses that gets rejected by Nice King. She makes a cameo in the episode "Ricardio the Heart Guy," when Ricardio is giving Lumpy Space Princess a Best Friend Massage.
She also makes a cameo in "Mortal Recoil" as one of the people following Princess Bubblegum into the hospital, and in "Wizard Battle," she is in the audience of the event. In "The Lich," the gem from her crown was taken by Finn and Jake as she slept. It is shown in "Princess Day" that she is considered a registered princess.
She is one of the very few characters in the series to have a nose. She wears a green dress and has a large emerald as a crown on her head. Like her dress color, her skin is green. She also appears to be wearing a hood or shawl, although this may be her hair or part of her crown. She has a particularly large posterior, but that may be a fold in her dress. [Source: wikia]
You can download the papercraft template here: Adventure Time - Emerald Princess Free Papercraft Download