How do you picture a Hex Cage?

So, I was gathering background on my chosen wych cult, The Seventh Woe (there isnt much background apart from they prefer hunting Tyranids). On page 23 of the codex, there is a little background which mentions the use of Hex Cages to capture Tyranid Creatures....

"The Cult of the Seventh Woe captured many of the alien monsters in Runic Hexcages before disappearing into the webway"

I want to include some of these in my army for aesthetic purposes, possibly as objective markers, or on raiders etc. Was wondering how you guys pictured them. Something made out of a solid material with glowing runes, some kind of force field, impassable immaterial bars or something completely different?

I imagine them to be little blue balls that are thrown at the creatures, creating an impeetrable sphere-like shape around the Tyranid. I imagin it to consist of hundreds of Hexaganol sides with runes etched onto them, and when the creature lashes out against the surface from the inside it causes pain akin to that of an Agoniser, not fatally so, however.

When touched I imagine them to flash like lightning from their normal dark blue, cliché force-fieldyness into a blinding bright light.

Cavash wrote:

I imagine them to be little blue balls that are thrown at the creatures, creating an impeetrable sphere-like shape around the Tyranid. I imagin it to consist of hundreds of Hexaganol sides with runes etched onto them, and when the creature lashes out against the surface from the inside it causes pain akin to that of an Agoniser, not fatally so, however.

When toughed I imagine them to flash like lightning from their normal dark blue, cliché force-fieldyness into a blinding bright light.

Gotta catch 'em all.

I imagine hex cages to be a bit like the Ghostbuster's ghost trap. DE's arcane wargear seems to be a lot of small boxes and trinkets that when opened create big whirling, unpredictable outcomes. So the hex cage could be some kind of small device that has Tardis-like properties in which the victim is sucked into the small, runed device and stored for easy transportation (With glowing runes to indicate a prisoner within). If you look at the raiding vehicles there wouldn't be much room to transport huge energy cages containing the trapped nids (unless they bring down the big slave barges) but a sack full of small glowing cubes would be far more convenient. Remember these dudes are pretty good at using trans-dimentional portals, and so the device could be some kind of link to a tiny sealed pocket of webway or something similar.

That said I can also see a hex cage being similar to what Cavash suggested.