Ants making cacoons?

Question

i was doing a science experiment and i had a fishbowl full with ants in it and i put a piece of bread in it and in two days a cacoonish thing was around the bread and they slowly started pulling it underground what is happening?

Answer 1

Ants often grow molds on food to feed to the nest.  Maybe it has naturally molded or they are doing this.  It's a fishbowl after all and maybe they don't have anywhere else they can do it.