☢️ Radioactive is one of the animated emoji in Google's Noto Emoji Animation set — the same radioactive emoji (U+2622 U+FE0F) drawn as a short looping Lottie animation. Lottie files are vector, so the animation stays sharp at any size and is usually much lighter than a GIF or a video.
☢️ is the radioactive emoji, part of Unicode's Symbols group, added in Emoji 1.0 (2015). Unicode's keyword list links it with “sign”.

