Basically i used wait 2 times waiting for arachnid expansion each time and saving for each expansion. On the third time i saw that my body killed it so I ate food and increased my wait time to 2 hrs..., The arachnid expanded and i saved but after that it stopped doing anything.
Then i tried reverting to the previous save and it persisted in doing nothing..... Then I hit reload and started a new game and it still would not do the expansion it previously did.
So the error persisted through a saved game and a reload...
I don't know how this game works , but errors should go away after new-game start or loading of a save file, or after reload (all saves should be stored in .sol file, if its in cookies its gonna be a problem or if its in the temp files)