She [wrote] one of the very early episodes with Eileen in it, and she had some really funny jokes in the way she pitched it.
[It was] just the way her voice sounded – she [had] to be that character!
This outfit is seen again in "Cruisin'" and "One Pull Up".
In later episodes, in Seasons 3 and 4, she started to wear sweatshirts, likely because the weather was colder at the time.
However, she looks nothing like a mole, she looks very much like a human, excluding her toes and tail.
She wears red glasses and has two eyelashes on each of her eyes.
We even tried an actor, but it just wasn’t playing funny.
In "Brain Eraser", her glasses did not have white in them, and they were narrowed down, showing her pupils.
Her most common outfit outside of work, especially in Season 8, is a pink t-shirt and blue jeans with the cuffs rolled up.
In Do Me a Solid, her attire outside of work was a pink shirt with ruffles around the neck and a blue skirt.
Her earlier appearances show her as coming off as weird, doing things such as burying golf balls in a sand trap saying she just laid baby sea turtle eggs and she's going to swim off to sea, and saying that she got lost in the woods a lot the previous year, saying she was going through a phase.
Minty Lewis describes Eileen's first appearances as coming off "as a pretty big weirdo nerd with major hots for Rigby".
is between a supporting character and a main character in Regular Show.