Treasure Goblin Portals? (Possible spoiler, depending on how anal you are)

[Vinicide]

So according to the lore thing that came up when I first encountered one of these, it said something about people being able to jump into their portals and being taken to a magical treasure land of awesomeness (that's totally verbatim!) Is this just for flavor or is there some way to jump into their portals? I've tried clicking on them but nothing's been happening.

[Dakia]

I'm pretty sure that you can't. You just need to kill them before they escape in to their portal.

[Lysah]

Wirt's leg, aspect of avarice, secret magic pony cow level, etc.