That seems reasonable...
I might build such a power something like this:
Webbing [-2]: You are capable of creating webbing, or some other material that can be used to entangle and bind foes of various sorts.
Important Skills: Might,
Real Stuff: Your webbing actually exists physically, and can be used for mundane things such as rope, makeshift clothing, and other such things. Depending on where it comes from, it may dissolve into ectoplasm eventually, but it certainly lasts at least the rest of the day.
Entangling: Your webbing can be used to entangle foes at up to one Zone's distance, using the normal Grappling or Maneuver rules and your Might skill. You recieve +1 to Grapple while using this effect, cumulative with any other bonuses you recieve to such.
Spinning The Web: You may also leave webs behind you, effectively 'trapping' a particular Zone. These traps will attempt to impose a Block on all actions on anyone entering the Zone, they do this with your Might score and any bonuses you recieve to Grapples, but are not technically grappling for rules purposes. These webs do not effect you, but do effect anyone else entering the zone, including friends and allies. Constructing a Web of this nature is a full action in combat, and may only be done while you are alone in the Zone in question. There is no limit to the number of Zones you can trap...but the webbing doesn't last forever, either becoming weakened or dissolving to ectoplasm within a day at most.