What is Shaco's Box and why can't it proc Dark Harvest (And why Can't his clone auto's either)

Hello all,

I'm just wondering what is Shaco's box viewed as in coding? Is it a trap like Nidalee's, Jhin's or Teemo's? Or is it a pet like Heimer's turrets or Zyra's plants.

Why doesn't it proc Liandry's like any of the previously mentioned characters skills?

And why won't it proc Dark Harvest anymore?

Is this a bug or intended?

Thank you for your time.