Good day. I have a character whose abilities revolve around creating "warp bubbles" in space-time. The general idea is that such "bubbles" will diminish and collapse over time (since the universe doesn't like its fundamentals messed with). Drain and Aid both have built-in "decay" features, so they work well.
Now, let's say you want to expand to Barrier. A normal Barrier sticks around until it's destroyed or dismissed (if you buy that Adder). You want to create a "warp bubble" that decays over time. Making it a Constant power doesn't work; it just collapses immediately when you turn it off. Other than the obvious Limited Power option (say, "Loses 5 AP per turn", -1/4), what options would you consider to build this?