I never liked Grimer/Muk. Then in B/W2, I caught a shiny Grimer in Castelia Sewers. It was my very first shiny after having played the series since the start, so of course I had to put it in my team even if I didn't really like it. And it really wasn't that good... until it evolved to Muk, and became of of my powerhouses. And I of course transferred it up to X/Y.
It's still not my absolute favorite line, but I'll always like it now.
