Drop to summon lightning. Left-click to kill ANYTHING IN ONE LEFT CLICK!!! After the sword is summoned, DO NOT pick it up yet. Make the redstone clock in the video. connect a command block to it with the command in the source commands section. Make sure the clock circuit is on and active. Now you can pick the sword up. throw it to summon lightning! Using this tactic, I will make a Throwable spears! command on www.minecraftcommand.science. soon.
First, you must give yourself a command block (If you are on a server, you must be 'OP'ed, and have access to /gamemode 1)
To get a command block, type /give @p command_block in the chat.
Once you have a command block, right click it to open it's GUI.
Now, you must copy and paste the command from your browser into the game. Select the entire command from below, then right click and press 'copy'.
Next, go back to your minecraft world, and paste the command you just copied into the command block. There are a few different keys that may be used to do this, depending on your keyboard. The most common ones are 'CTRL + V', 'COMMAND + V', or 'STRG + V'
Finally, you can press done to exit the GUI, and execute the command block by powering it with a redstone block, a lever, or any thing you can get your grubby hands on. Just make sure you don't place it on top of the command block, or the machine will not be installed!