hey
in this instructable I will show you how to make a Nerf Grappling Gun, that's kind-of like a Batman version. (Not necessarily.)
I apologize for any non-good lighting in my photos. anyways, lets get to building.

Step 1: The Materials

Okay, you will need the following materials in the picture, and i will list them too.

one Nerf gun (a pistol, with pull-back handle)
one #3 Lego rod
three Lego "cross-connectors"
one "headless" Nerf dart
one "Delta connector" (a tri-connector)
three Lego "insect legs" (is that what you call them???)
a large Lego cone (optional & not pictured)

Step 2: Putting Together the Hook

you start by putting the Lego tube inside the headless dart where the dart's "head" would've been. you need to put it in all the way so it can stay in there and the hook won't come out that easily.

Step 3: The Hook

you need to put together the actual hook to put on the dart.

you need to take the other pieces and put them together as the pictures show

Step 4: The Final Product

put the hook into the dart through the end where you stuck the tube into.
then put it into the gun.
(i would recommend that you do a air restrictor mod to the pistol so you get a better range with the grappling hook, as it's heavy)