Grok nails it:

“No, there is no official seahorse emoji in the Unicode standard (which governs all standard emojis across platforms like iOS, Android, and web). A seahorse was proposed for inclusion in 2018 but was rejected by the Unicode Consortium, and no version of it has been added in any subsequent releases up to the latest Unicode 16.0 (September 2024).

This absence has sparked a viral "Mandela effect" online, where many people vividly recall a seahorse emoji that never existed—possibly confusing it with stickers, custom graphics, or similar sea creature emojis like the tropical fish (🐠), blowfish (🐡), or octopus (🐙). Large language models like ChatGPT have even been observed glitching or looping when prompted about it, cycling through unrelated emojis in an attempt to "find" it.

If you're looking for seahorse-like visuals, you could use alternatives like 🐴 (horse) + 🌊 (water wave) for a DIY combo, or search for seahorse stickers in apps like WhatsApp or iMessage.”