A Drakon Prosecutor first used this on the Empire's return to Mobius. Angered that Sonic the Hedgehog refused to remain motionless, the Drakon used the staff to increase the gravitational field in the room, bringing Sonic, Tails and Doctor Robotnik crashing to the ground. Robotnik was then granted the staff's powers, instead choosing to create a glove that can summon Mobius Rings.
Sentinel staffs also seem to be able to electrocute their targets, something Sonic learned when he was taken to Drak for his "crimes". Choy later stole one when Hobson defeated a Prosecutor (and named the staff in the process), summoning a Mobius Ring that took them to the Rusty Ruin Zone. When Grimer "betrayed" Robotnik and joined the Drakons, he eventually managed to alter his own staff so that it could teleport all the accompanying Drakons back to Drak before creating a Mobius Ring to rejoin his master.
Interestingly, Sonic was given a dimensional staff during his return to Drak. The hedgehog first used it to plant the Chaos Tap before summoning another Mobius Ring to take him to the Death Carrier. It was presumably left there as the battleship fell out of the sky.