Electricity Mastery was the only set that really made sense for a Storm/Sonic based on the electric powers in the storm set. It also nicely synergizes with the powers I already have.
Electric Fence
Hold still
 | Score |  | 1 of 5 |  |
| Unslotted Strength | | 3.3 x Brawl | |
Summary
This is the same single-target immobilize power that blasters are forced to take in their secondary. It's low power and of little use.
How to Use
If you're desperate to keep something from running away, perhaps this will have some use for you. Also, you can immobilize them and let Tornado and Lightning storm rip them a new one (assuming you're not here just to read about the pool and not building a Storm/Sonic).