Casting Walking Bomb on a target removes the detonation effect of previous instances of Walking Bomb and Virulent Walking Bomb. The timer of the damage over time effect of previous bomb instances is reset to the full 20s and the damage amounts are set to the value of the last bomb.
The spell claims it is nature damage, however it is actually spirit.
The explosion is physical damage and has the same gory appearance regardless of the target.
Due to the large amount of Threat, the bomb will likely run for the caster. Immobilizing spells should be used on the victim. Shattering using Stonefist, after using Petrify or Cone of Cold will detonate the bomb immediately.
The spell works well in conjunction with Waking Nightmare, since Waking Nightmare can result in tightly-clustered enemies with no party member close by (it is imperative to immobilize the bomb).
This spell also works with Blood Control as the bomb will turn and run back at enemies.