>>29386729Weezing. Its recovery is garbage so you need Black Sludge and Koffing's stats are complete trash even with the boost to its defenses.
You'd have no offensive pressure and constantly be in fear of catching a stray Knock-Off from something.
Also, don't use Sludge Wave. You aren't a sweeper and the extra 20% chance to poison is infinitely more valuable compared to an extra 5 BP.
I also wouldn't use D-Bond either, Weezing is too slow to abuse it well. Something like Haze, Flamethrower, or Toxic Spikes would be more useful.