Wormhole Thresher

Wormhole Threshers are small adult threshers. This variant of thresher can pull enemies toward it, impaling them on the various spikes covering its body. Their target will take constant damage while in contact, until either they weaken the thresher enough to break free or it simply lets go. If there is enough distance between the thresher and an enemy, it will fling spikes. In True Vault Hunter Mode, they are renamed Black Hole Threshers and the range of their singularity is improved.

Strategy
Taking them out from a distance before they suck you up in their blackhole is a good strategy. Also, wearing a spike shield is really effective, when they "blackhole" you, the shield will attack the thresher and let you free. A good shotgun can also be really effective when stuck in his singularity field.