Temmie is a species of monster in the Underground. They appear as a unique enemy in Waterfall, residents of Temmie Village, and the vendor of Tem Shop.
Contrary to popular belief, killing Temmie accrues EXP and is considered a kill by the game, which will cause a True Pacifist Route attempt to fail.
They live in the Tem village, the Temmies are all girls and they are all named "Temmie" except for "Bob".
Temmie doesn't like muscular things because of the catchphrase "NO!!!!! muscles r... NOT CUTE" in which Aaron appears to flex at Temmie.