Based on an existing pattern, we can probably infer the following about Gen 7. That it will include a two-stage Poison evolution line -based on toxic waste:
Gen 1: Grimer/Muk Gen 3: Gulpin/Swalot Gen 5: Trubbish/Garbodor Gen 7: ???
How are Gulpin and Swalot ugly? the others I can agree with because they seem MEANT to be ugly, but Gulpin and Swalot are just cute blob things with dot eyes, not a pile of sewage like Muk, and not a nasty pile of trash like Garbodor, but those two are ugly in a good way.
"Greater love hath no man than this, that a man lay down his life for his friends. John 15:13"