Snakes. Why'd It Have To Be Snakes?

The name of the Achievement is a quote by Dr. Henry Walton Jones, Jr. (Indiana Jones for the uninlightened) from Raiders of the Lost Ark

On Heroic, you can avoid getting any small green snakes at all for the whole fight, and easily get this achievement without using any AoE

1. Clear the room with the three large piles of bones, after Slad'ran's room.
2. Have Healer stand by the entrance to the Colossus's room
3. Have the tank quickly run boss to the lower end of the farthest of the three bone piles and tank him there. This is much easier than it sounds because he'll stop chasing you to cast poison bolts and novas along the way, giving you good distance.
4. Kill Vipers (the bigger snakes) as they come by.

You'll only get viper adds that way, and you can easily kill them off as they come by. If you wipe, you'll see all the green snakes sitting under the snake statues in Slad's room. You were tanking him too far from them for him to call them over when they spawned. These green ones do Snake Wrap, and avoiding them altogether makes this boss much less difficult. Now he's just a "Kill Vipers, avoid Nova" easy lazy tank and spank. Just remember you'll have to kill all those idle snakes in his room once you go in to activate his altar.

You can also clear Colossus first, and tank him in the middle of that room if you want.

GL!

Edit, March 11 2009: They seem to have modified the fight so that you will get some small snakes even in the Colossus room, but still nothing like if you fought in Slad's main room. The small snakes are also now despawning when Slad dies.

Unfortunately the snakes have dropped by their local YMCA and took some swimming lessons because I found that out the hard way today when they came and gave me a huge hug...