说曹操曹操就到

Cao Cao (155-220 CE) was the cunning warlord of the Three Kingdoms era. The saying comes from 《三国演义》 (Romance of the Three Kingdoms), where messengers urging Emperor Xian to summon Cao Cao for protection find that Cao Cao's army has already arrived, proverbial for someone showing up the instant they're mentioned.

Often shortened to just 说曹操曹操到. Same playful 'speak of the devil' moment as in English, but with no negative connotation about the person; Cao Cao's reputation does the work.