Sure, you might have heard this when i tried to shout it to you (stuffing :l), but it might be a good idea.
I want monster spawning eggs at mall.
They would be sold at the pet shop.
Sure, they are infinite-use on Creative, but they are one-use on Survival.
I found that out when Tammy accidentally dropped a zombie egg, and i used it in the middle of lot of wolves that Tammy spawned. Bam. Instant "AAH I MISSED THE ZOMBIE IM BEING TORN TO PIECES SAVE ME".
And the damage values? Its totally possible.
Damage values of eggs are the same as the spawned entity's IDs, so its possible to spawn primed TNT and boats. Heck, maybe sell boat eggs in the sailing shop.