sponge

someone able to acquire new knowledge and skills rapidly and easily

“she soaks up foreign languages like a sponge”

ask for and get free; be a parasite

a follower who hangs around a host (without benefit to the host) in hope of gain or advantage

primitive multicellular marine animal whose porous body is supported by a fibrous skeletal framework; usually occurs in sessile colonies

a porous mass of interlacing fibers that forms the internal skeleton of various marine animals and usable to absorb water or any porous rubber or cellulose product similarly used

erase with a sponge; as of words on a blackboard

gather sponges, in the ocean

soak up with a sponge

wipe with a sponge, so as to clean or moisten