Keep the same stats but change the active to this:
Target an enemy champion within 800 units. For the next 5 seconds, you take 50% reduced damage from any source other than that champion but deal 50% reduced damage to anything except that target. This effect ends if the champion moves further than 1000 units away from you or dies.
Isn't this basically Poppy's old ult? Also your survey implies that this would be a reasonable change. I for one would vote "Try something else"
I personally want the active to be something fitting with the "Ohmwrecker" name. I was thinking something similar to a gunblade active, where you zap a champion (or maybe an area, potentially even a tower+ surrounding area) and deal magic damage and silence enemies for like 0.5-1 seconds.
I think that this item's active should be something similar to what it currently is but change what it does to towers, so for example have this:
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Active: Target an enemy tower and for the next 5 seconds the targeted tower will take X% extra damage from all sources.
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But the idea you had sounds interesting for a complete new item though.
