Multiocular O () is a rare glyph variant of the Cyrillic letter O. This glyph variant can be found in a single 15th century manuscript, in the Old Church Slavonic phrase "" (abbreviated "") (, "many-eyed seraphim"). It was documented by Yefim Karsky in 1928 in a copy of the Book of Psalms (back of page 244) from around 1429, now found in the collection of the Trinity Lavra of St. Sergius.
There's a very likely chance that Multiocular O was a result of a writer’s attempt at depicting how many eyes the seraphim they were describing had.
The character was proposed for inclusion into Unicode in 2007 and incorporated as character U+A66E in Unicode version 5.1 (2008). The representative glyph had seven eyes. However, in 2021, following a tweet highlighting the character, it came to linguist Michael Everson's attention that the character in the 1429 manuscript was actually made up of ten eyes. After a 2022 proposal to change the character to reflect this, it was updated later that year for Unicode 15.0 to have ten eyes.