Phylum Porifera.. 5000 known species... Reproduction by sponges is by both sexual and asexual...
Humans have been very mean to them.. we dried them out completely, blasted them with radioactivity and yet they continue to live... we have also cut them into tiny pieces but they do the same thing as in Terminator 2.. if you put all the bits in water they will connect together and form the Phylum Porifera (sponge) it was before.. even if you drop 2 in they will only pick up the bits that were theirs before.. so one will find all his/her bits the other will find theirs and they will become 2 sponges again both with be exactly the same as they were before you cut them up.