I discovered that you can make a golem with MCreator that spawns in when you built a certain structure! The only problem is that you need a custom block in order for it to work, e.g. you can't make a golem spawn in with just dirt and and a pumpkin. It has to have a custom block somewhere in the structure. I have a block in a mod I'm working on called Dormant Phyrothite, and it is a black metal. I want a Phyrothite golem (a mob I made that is basically a black and purple iron golem) to spawn in when I build a "T" out of Dormant Phyrothite, and put a pumpkin on top, similarly to a traditional Iron Golem. For instance, in the Update Tick event of Dormant Phyrothite, I selected the condition Block At (DON'T select !Block At), and then I selected Dormant Phyrothite. In the condition box, where it said [i,j,k], I changed it to [i,j-1,k]. This makes it check for if there is a Dormant Phyrothite block under the central Dormant Phyrothite. Then, on the left, I selected Stack Event, and clicked the Add Event button in the middle (not the one on the bottom!!!). In the condition for this new event, I did the same thing as last time, except I made [i,j,k] into [i-1,j,k]. I repeated the Stack Event, and Add Event another time, with the same Block At condition, but made it [i+1,j,k]. Again, Stack Event and Add Event, but this time, when I did the Block At condition, I selected a Pumpkin, and changed [i,j,k] to [i,j+1,k]. One last Stack Event and Add Event. In this event, I spawned in the Phyrothite Golem. I selected the Add Event button on the bottom, and then selected the Add Event button under the Stacked Event. This time, I did the event Remove block, and chenged j to j+1. Add Event on the bottom, Add event in the middle. Same thing, I selected the Remove Block event, but changed i to i-1. I repeated the Remove Block event 3 more times, once changing i to i+1, once changing j to j-1, and the last time, keeping i, j, and k the same. I spammed Add Event on the bottom until you get back to the first page. This is going to sound awful, but, I had to do this entire thing again under the Update Tick Event, but I did all the changes you did to i to k, e.g. change the Block At [i,j,k] to [i,j,k+1], where I did [i+1,j,k] the first time I went throught the process. Then, I finished the block, and started the Test Environment. I built a "T" out of Dormant Phyrothite, put a pumpkin on top, and voila! A Phyrothite Golem spawned just like an Iron Golem would! I'll be making a video tutorial for this soon as well if this was a TL;DR, or if you just don't understand it.