The Twister is a small, gravitational/kinetic anomaly that's usually imperceptible. The only way to notice a Twister is if it's interacting with any small, loose objects in the area or if local flora and fauna are avoiding its radius.
Whenever anything organic, or anything moving at high speed and not of great enough mass to be unaffectable by the Twister, enters the anomaly's radius, the anomaly becomes "active." In its inactive state, it usually just moves small, loose objects in a manner reminiscent of a stationary "dust devil." A miniature tornado, in other words. When active, however, its spin accelerates to completely impossible levels for a brief few seconds before it violently ejects whatever it has picked up in a seemingly random location.
While leaves and dust are of no danger, even something as ordinary as a handful of pebbles could end up acting like grenade shrapnel after a tangle with a Twister. It's so far unknown what exactly would happen if a human was to enter one of these anomalies.
