The Lua script requires several changes to work with the current engine.

Also, because the unit is not animated, I think it would be better to crop the image so that it doesn't repeat.  Copy the dummy animation from units/rocks/unit-rocks.lua for example.  Actually though, I think the non-animating animation should be moved to some global file and then used from there, instead of being repeated in each unit.

I hope this mushroom patch is added to the game.  Its color would be a nice contrast to the morels.  Were you going to make it harvestable?