We've all summoned Herobrine using command blocks, but it's much funner to summon him with a ritual. In this tutorial, we learn how to allow players to summon Herobrine with a ritual of your choice!

This is very basic. First you need a command block, chain command block an repeating command block. Get them with the following commands:

Next you place down a normal command block and put in the /summon command that you desire to test it works with 1.12. If it summons your desired mob, you can continue. Otherwise, keep trying until you get it to work.

Once that it done, make many scoreboard objectives. The more blocks required, the more scoreboard objectives. To make one, do:
And change the "Block1" to Block2,Block3, etc when you add more blocks. If you have 8 blocks in the ritual, go up to Block8.

Place a repeating command block, set it to 'Always Active' and type in the following command (you don't need a repeating command block, I just find it clearer to differentiate between normal and always active command blocks):
Change the x,y and z variables to the coordinates of the desired block relative to the Armour Stand. For example, if the block is one block away in the x axis, 2 away in the y axis and 0 blocks away in the z axis, do ~1 ~2 ~0. You can see this by pushing F3 and simply counting the amount of blocks in each direction. Then change BlockID to the id of your block (see the id with F3,H and hover your mouse over the block) and change Type to the block type. For example, if you want to detect red wool, do "wool 14".

Then place a chain command block where the repeating command block is facing (look at the arrows on the sides) and put this command into it:
Change the x,y and z variables to what you set them to before. What this command does is detect if the block was removed, preventing cheaters from summoning your desired entity without doing it properly.

Continue the command block chain, going back and forth between those two commands, changing Block1 as the block being detected changes. If you don't have any ideas for the ritual, just make a command block chain with these commands, making a new command block for each line:
Yes there are a lot of command blocks, but this honestly isn't a lot for map makers or command block freaks. When you have finished your setup, move on

Make a new scoreboard objective named "Good" by doing "/scoreboard objectives add Good dummy" and do:
Change x1,y1 and z1 to the coordinates of one corner relative to the Armour Stand and x2,y2 and z2 to the coordinates of the opposite corner. In the example I have given, the coordinates would be ~-1 ~-1 ~-1 ~1 ~0 ~1, but if you have made yours bigger, then change the coordinates to match your ritual. Then change BlockID and Type to fit a block that has been used. If your ritual used more than one block type, you will have to make more chain command blocks. For the example I have given, you will need to use three chain command blocks and do:
Be sure to put each set of execute commands into separate command blocks. Finally, place two more command blocks and put in the following commands:
And then finish your /summon command. After that, you are finished and good to go! Some things you might like to try include summoning a megaslime with "/summon slime ~ ~50 ~ {Size:20}" or you can change the armour stand to a creeper or pig and do "/summon lightning". If you are feeling confident, you can also make particle effects to jazz it up. If you want an item spawning ritual, you can make it so it doesn't delete and look up how to summon that item (I still don't know yet). Want a real boss fight? Summon another armour stand that's invisible and make a lot of easier mobs constantly spawn at its location. When doing all of these, make sure the "/kill" command happens after the original armour stand is no longer useful.

If this was helpful, please give this blog a diamond and comment down below. If you like what I do, feel free to subscribe bc I post cool stuff every once in a while. Lastly, don't feel like you have to credit me. I got this idea from somebody else and they probably took it from somewhere else :)