Gudetama is a Sanrio character created in 2013. He is a lazy, lethargic egg.
At first I thought it was a really strange idea for a character, but after seeing the character in action (in short animations, comics, and Twitter pictures), his unique personality came to grow on me--probably because I'm pretty lazy myself.
Lawson started selling Gudetama-themed foods starting in late March. They are limited in quantity, so best not to wait if you see them and want to try them!
Here are some of the sweets I have managed to try so far:
Egg Bread くでたま たまごぱん (gudetama tamagopan) 130yen *may still be available*
Gudetama Pudding くでたま プリン 240yen *should still be available*
More Gudetama Information:
Gudetama Sanrio Character Page (Japanese): http://www.sanrio.co.jp/character/gudetama/
Gudetama Short Animation Playlist (Japanese): YouTube
RocketNews24: "Meet the most unmotivated Sanrio character ever -- Gudetama, the lazy egg!"