U+1F480 · emoji since 2010
Online, the skull emoji almost never means death. It means I'm dead, as in something is so funny it killed me. For a lot of people it has fully replaced 😂 as the top laughing reaction.
It also covers embarrassment and disbelief, like when someone says something so unhinged you simply perish. Context is everything: on a Halloween post it's spooky, under a meme it's the highest compliment comedy can get.