What will Poppy prevent/negate from working with his W? Dashes, Blinks, Pulls? Let's talk.

I think what we need is a very easy to understand description of what Poppy will "negate" when W is active. For example, you have (dashes, blinks, pulls,) we're told his W prevents target dashing, whether they're trying to come in, or leave. So, what would you classify a Amumu (q) coming in be? What would you classify a Thresh (q 2nd active) coming in be? In the video description Lee sin is unable to come in upon reactivating (q).

My last match as poppy, Hecarim was able to come into and out of my W while he was doing his dash, and Amumu was able to come into me upon landing his Q which I would argue he "dashes" to the enemy he hits. My W did not prevent either of these.

Anything that would either bring poppy in, or anything that would bring somebody into poppy. What exactly does his W prevent? What exactly does his W not prevent?

1. Dashes - Leblanc (w), Aatrox (q), Alistar (w), Fiora (q)
2. Blinks - Ezreal (e), Ekko (e), Kassadin (r), Shaco (q)
3. Pulls - Blitzcrank (q), Darius (e), Nautilus (q)