The only way to spawn some Engender Mobs is with a fusion, and these mobs are not hostile with the player that spawned them. Now, Golems are mobs that can be built/constructed, by placing 4 iron blocks and a pumpkin. Now, this would spawn a Minecraft Iron Golem. But what if a player wants to spawn an Engender Iron Golem that is hostile with its creator/other players? Instead of making a fusion (that would spawn a golem that is neutral with its creator), the player should be able to build the classic Iron golem structure, but with emerald blocks filling the space for air blocks. this will spawn an hostile Iron Golem. For the Magma Golem, a simple T structure of magma blocks with a pumpkin should be able to spawn it (as seen in Minecraft: Story Mode); Ice golems with a T structure of snow blocks and pumpkin, and for the Prison Golem a T structure of Obsidian Blocks and a pumpkin (the Sunshine Institute was made with mostly Obsidian, and the golems had its same color). Now, The Wither Storm should be able to follow these rules. Soulsand blocks, a Command Block in the middle and 3 Wither Skeleton Skulls. This can spawn a Wither Storm hostile to its creator. This can be useful for anyone who simply plays in survival and wants to obtain the Withered Nether Star, normally they can't kill their own mobs and the Wither Storm can only be spawned with a fusion, making it unkillable by the player who summoned it (of course, make the command block placeable on the ground in Survival, and maybe a tool that can break it)
The only way to spawn some Engender Mobs is with a fusion, and these mobs are not hostile with the player that spawned them. Now, Golems are mobs that can be built/constructed, by placing 4 iron blocks and a pumpkin. Now, this would spawn a Minecraft Iron Golem. But what if a player wants to spawn an Engender Iron Golem that is hostile with its creator/other players? Instead of making a fusion (that would spawn a golem that is neutral with its creator), the player should be able to build the classic Iron golem structure, but with emerald blocks filling the space for air blocks. this will spawn an hostile Iron Golem. For the Magma Golem, a simple T structure of magma blocks with a pumpkin should be able to spawn it (as seen in Minecraft: Story Mode); Ice golems with a T structure of snow blocks and pumpkin, and for the Prison Golem a T structure of Obsidian Blocks and a pumpkin (the Sunshine Institute was made with mostly Obsidian, and the golems had its same color). Now, The Wither Storm should be able to follow these rules. Soulsand blocks, a Command Block in the middle and 3 Wither Skeleton Skulls. This can spawn a Wither Storm hostile to its creator. This can be useful for anyone who simply plays in survival and wants to obtain the Withered Nether Star, normally they can't kill their own mobs and the Wither Storm can only be spawned with a fusion, making it unkillable by the player who summoned it (of course, make the command block placeable on the ground in Survival, and maybe a tool that can break it)