火炎焱燚
huǒ yán yàn yì
hot (i.e. popular) (emphatic form of 火[huo3]) (neologism c. 2016)
fire (火) + fire (火) + fire (火) + fire (火) = blazing viral heat
This four-character set is a visual intensifier: each step doubles the fire until 燚 stacks four 火 into pure spectacle. It became a 2016 internet neologism precisely because the escalating glyph mirrors the idea of something going wildly viral.
这首歌最近火炎焱燚，到处都能听到。
zhè shǒu gē zuì jìn huǒ yán yàn yì，dào chù dōu néng tīng dào。
This song has been super popular lately; you can hear it everywhere.
那个短视频火炎焱燚，一夜之间获得了几百万的点赞。
nà ge duǎn shì pín huǒ yán yàn yì，yī yè zhī jiān huò dé le jǐ bǎi wàn de diǎn zàn。
That short video went incredibly viral, racking up millions of likes overnight.