U+A7C4 Latin Capital Letter C with Palatal Hook

The Wikipedia has the following information about this codepoint:

The palatal hook (◌̡) is a type of hook diacritic formerly used in the International Phonetic Alphabet to represent palatalized and prevelar consonants. It is a small, leftwards-facing hook joined to the bottom-right side of a letter, and is distinguished from various other hooks indicating retroflexion, etc. Theoretically, it could be used on all IPA consonant letters, – even on those used for palatal consonants, – but it is not attested on all of the IPA letters of its era. It was withdrawn by the IPA in 1989, in favour of a superscript j following the consonant (i.e., ⟨ƫ⟩ becomes ⟨tʲ⟩).

The IPA recommended that esh ⟨ ʃ ⟩ and ezh ⟨ʒ⟩ not use the palatal hook, but instead get special curled symbols: ⟨ ʆ ⟩ and ⟨ʓ⟩. However, versions with the hook have been used and are supported by Unicode.

Palatal hooks are also used for Lithuanian dialectology in the Lithuanian Phonetic Transcription System (or Lithuanian Phonetic Alphabet), including the exceptional form ꞔ, which is not a c plus palatal hook but rather a graphic variant of ᶃ once recommended by the IPA.