Craftable Mob Spawners (Or something like it)

 

What if instead we didn't just have a Mob Spawner? Because if we did make them attainable, people could just grab them out of Dungeons as they are pretty common. So what if instead we had a different block, have a recipe including pretty rare items like Heads and some sort of Internal Flame or some kind of item that can sometimes drop when breaking a mob spawner, this will be the item that goes in the center of this new block.

 

So, ok? What would this do? You need Mob Spawn Eggs to even have a Mob Spawner spawn anything, no way Mojang adds though to the game that's ridiculous, remember what I said about a cost? So how about you could use this object by right clicking it, In this screen you would have to put Soul Sand into it, and just like Enchantment Tables, have it cost XP to turn it on. Now if a mob dies near it, the block absorbs the particles and now becomes a Spawner of that Mob! This would not work for say, Ender Dragons and Withers, and it would not be forever, you need the exact number of soul sand for each mob spawned, and each Soul Sand that is placed into it cost more and more levels. How do you guys feel? Should this not be in the game? i thought it would be a pretty cool idea since it is one of the only blocks that you can't get in survival besides Bedrock.