Temmies resemble dogs, with cat-like ears on top of their heads as well as dog ears on the sides, shoulder length black hair, and blue shirts, excluding the Temmie Shopkeeper, who has gray hair and a striped blue and yellow shirt instead.

Temmie Chang says that Betty Kwong designed Temmie originally. Temmie liked the doodle so much that she used it as a mascot for years until it made an appearance in Undertale.

All Temmies share an erratic manner of speech, where they often exclude letters, mix lower and upper cases, make inconsistencies, etc. There are some exceptions, however; Bob always speaks in perfect English, the Temmie Shopkeeper speaks in fluent English when the protagonist refuses to sell an item she wants, and regular Temmies in-battle speak in somewhat proper English when denied Temmie Flakes.

In battle, Temmies find the protagonist to be adorable and refer to them as such despite attacking them. However, they also find muscles to be disgusting, as evident by their negative reactions to the protagonist's flexing should they choose the "Flex" option. Because of this, when Aaron, a monster who has tight muscles and an obsession for flexing, appears as a result of the "Flex" option, Temmies are so put off by them that they flee on sight shortly after.

LINES:
fhsdhjfdsfjsddshjfsd [Neutral]
hOI!!! i'm tEMMIE!! [Neutral]
awwAwa cute!! (pets u) [Neutral]
OMG!! humans TOO CUTE (dies) [Feed Temmie Flakes]
NO!!!!! muscles r... NOT CUTE | NO!!!!! [Flex]
NO!!! so hungr... (dies) [Feed Temmie Flakes, if the protagonist has no Temmie Flakes in their inventory]
FOOB!!! [Feed Temmie Flakes, if the protagonist has Temmie Flakes in their inventory]
can't blame a BARK for tryin'... [Feed Temmie Flakes, if the protagonist refuses]

FLAVOUR TEXT:
RATED TEM OUTTA TEM. Loves to pet cute humans. But you're allergic! [Check]
Special enemy Temmie appears here to defeat you!! [Encounter]
Temmie is trying to glomp you. [Neutral]
Temmie forgot her other attack. [Neutral]
Temmie is doing her hairs. [Neutral]
Smells like Temmie Flakes. [Neutral]
Temmie vibrates intensely. [Neutral]
Temmiy accidentally misspells her own name. [Neutral]
How'd you do that? [Low HP]
You flex at Temmie... [Flex]
Temmie only wants the Temmie Flakes. [Feed Temmie Flakes]
You say hello to Temmie. [Talk]