2. Bloated Well Zombie (Season 2, Episode 4: 'Cherokee Rose')
This is one zombie we can never un-see. The folks at Hershel's farm were about to draw water from the well when Dale noticed a walker splashing around in the well. The group decided that shooting the zombie would certainly taint the water with walker-guts so they tried to trap it instead. Except this particular member of the wading dead – sodden, turgid, swollen — did not go for their bait of canned ham. So they sent Glenn into the well to try to trap him; no one had counted on this bloated beast splitting in half, however, polluting the water with its goopy innards. Ugh.