Cuneiform Sign Udug

It is a cuneiform sign read udug for a spirit or demon.

Scholarly sign lists also record the Sumerian readings gidim₄ (“ghost”) and šedu₂ (“spirit”). A reading is the word a sign stands for in a text, not a separate character. The surrounding words, especially a qualifier such as hul (“evil”), decide which English meaning fits.

What is the history behind 𒌜?

It is a writing sign used in Sumerian ritual texts.

Cuneiform signs were pressed into clay with a reed stylus, first for practical records and later for many kinds of writing. Sumerian Udug-hul (“evil udug”) incantations have precursors from the third millennium BCE; most surviving manuscripts date to the first millennium BCE. In the bilingual Sumerian-Akkadian Udug-hul / Utukkū lemnūtu tradition, ritual healers recited spells for a distressed patient to drive harmful beings from the person and their surroundings.

Why does 𒌜 look different in fonts?

Cuneiform fonts can use different historical styles for one sign.

Unicode reference glyphs favor the Ur III style, while fonts for Old Babylonian, Neo-Assyrian, or other periods can draw signs differently or merge shapes. A different outline by itself does not mean the encoded character has changed.