Asian purseweb spiders, and among the strangest mygalomorphs anywhere: females with enormous, disproportionate fangs on a compact body, living sealed inside silk tubes and striking prey through the wall.
The keeping reproduces the tube: deep substrate, a vertical anchor, stable moisture, and prey introduced against the silk. The spider is essentially never seen; the tube's twitch is the display. Venom is undocumented and the standing mygalomorph no-handling rule applies on principle.
Asian supply is close to nonexistent, with occasional single animals surfacing on collector provenance. The genus trades on morphology to the small audience that collects extremes of spider anatomy, and the fangs, glimpsed once at a rehousing, justify the whole arrangement for exactly that audience.