Amy Nagashima, who also works under the professional name Amy, is a Japanese artist and character designer best known as the original creator of the Sanrio character Gudetama. Her full name in Japanese is Emi Nagashima, written as 永嶋 瑛美. She is a graduate of the Joshibi University of Art and Design.

Nagashima created Gudetama in 2013 while working as a designer for the Japanese company Sanrio, the organization known for Hello Kitty. The character was inspired by an experience after a long day at work when she was preparing tamago kake gohan, a dish of raw egg over rice, for dinner. She observed that the droopy appearance of the egg yolk looked cute and reminded her of the tired feelings of young people in modern society. At the time of the character's creation, Nagashima was twenty-six years old.

Gudetama was initially entered into a food-themed character competition held by Sanrio to generate new ideas, where it placed second. The winning character was a cheerful salmon fillet named Kirimichan, though Gudetama eventually surpassed it in popularity and became Sanrio's third most profitable character. The name Gudetama is a portmanteau combining the Japanese ideophone gudegude, which evokes laziness and lack of energy, with the word tamago, meaning egg.

Beyond Gudetama, Nagashima is also credited as the designer of another Sanrio character named Kaitouloppapu. She has been featured in Suki Chikara, a project promoting the empowerment of female artists. Regarding her artistic tendencies, Nagashima has noted that she usually creates female characters because she wants to express the beauty of women.

The Gudetama character has been adapted into multiple animated works for which Nagashima is credited as the original creator. These include the Gudetama television series, the online anime Gudetama Freestyle, and the Netflix hybrid live-action and CG animation series Gudetama: An Eggcellent Adventure. The character also appeared as a regular segment on the Japanese morning television program Asa Chan from 2014 to 2020.