say a zombie is following a player, and the player pillars up.
currently the zombie would break the bottom 3 blocks of the pillar and simply stare up at the player.
what i want the zombie to do:

1. jump 1 block upwards
2. place a configurable block below himself
3. break the block above the zombie
4. repeat

this feature is present in the epic siege mod, so that might be a good comparison

1048da5

there are some reasons why i didnt add it yet:
it cloggs up the world with whatever blocks the mobs build with
making a timed block that disappears would need me adding a block and thus making this mod not server side anymore. i kinda want to keep the mod server side

maybe have it start disabled?
i can see that some people might not like this feature, but i think that others would really like the functionality of epic siege in newer versions.
maybe allow some zombies to place ladders?
they can climb ladders already if im not mistaken.

in the epic siege mod the zombies used to place cobblestone, and even after a ton of days, it didnt really clog the world up, since the pillars would only be concentrated right by the player, who would thanks to simple instinct remove them as soon as possible.

but i can understand why you would want to keep it server-side.

maybe, someday, you or someone else, could create this and potentially other stuff as an addon for this mod.

i think i can remember a mod which added blocks, and as such was client- + serverside,
but could also disable this in the config, making it serverside only,
maybe you could try to recreate this effect

what if... instead of building... they start riding a flying mob. like a bee or parrot?