This Command Is Called Better Witches. As You Could Have Guessed It Adds Better Witches! Now They Will Summon Silverfish Roughly Every 15 Seconds Similar To The Witches In Clash Of Clans Or Clash Royale. Also They Can Shoot Lazors Watch Video For More Info And I Hope You Enjoy ~ Blue
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!