This is Unown.

Down below, you will see a group of Unown.

And this... is the fabled Mega Unown.

Mega Unown is a being only known in urban legends. Unown is known to travel through space and multiple dimensions. But, when Mega Evolved, its powers more similarly emulate the intimidting abilities of legendary Pokemon like Necrozma and Palkia.

hehe I'm a hidden easter egg~

Unown come in many different forms, 28 in all. Unown C is just one, while 25 others resemble the rest of the alphabet of the English language.

The latter two resemble an exclamation point and question mark, with more eyes that appear more tired. All of the unown forms can be seen here:

unown-c