There are plenty of ways to wreak havoc with a Nerf gun. The company has consistently outdone itself in recent years by releasing rapid-fire products that are more like actual canons than toys. For example, there's the Nemesis MXVII-1oK, which we already know spews foam balls at 70mph. When given a little love though, Nerf staples are easily transformed into formidable backyard weaponry.
Consider for a moment this behemoth: Youtuber Frank Cooper combined three Nemesis blasters, creating a hulking gun that carries 1,200 rounds. You'll notice that there's only one trigger commanding the three guns. That's because Coop772 created this unholy trinity by trimming the two battery components off the side blasters. The center gun's rev trigger commands all three flywheel sets, allowing ample artillery to flow from an overhead plastic bin, mounted on top.
The gun's positioning can be modified too, as Cooper allows for it to rotate and adjust its height. Clearly, the size of your victims is a non-issue.
Here's what this twisted machine looks like in practice: