to come来(ongoing -ing)着 tags onto a sentence to recall what was happening or said a moment ago — "(someone) was just …, what was it again?" It's casual and spoken. It has no negative form (never not不 / not / haven't没to come来(ongoing -ing)着), and in a question it appears only with what什么, who谁, or where哪儿.
Struktur: Sentence + 来着
yesterday昨天someone有人came来looking for找you你来着。
Someone came looking for you yesterday.
you你just now刚才were saying说what什么来着?
What were you just saying again?
Remember: to come来(ongoing -ing)着 = "…what was it again?" — a casual tag for recalling the just-past (you你just now (variant of 刚才)刚才variant of 说说what什么to come来(ongoing -ing)着?). Two limits: no negative (never not / haven't没to come来(ongoing -ing)着), and in questions only with what什么 / who谁 / where哪儿.
Hati-hati
- It's purely for the recent past — not the distant past, and not future.