This is one of the Field Runes.
It can only be used with level 25 and magic level 4 or higher.
||Field Runes (Earth Damage)
||adevo mas pox
||Any player with Magic Level 4+ and Level 25+
|Buy spell from:
||Buy made runes from:
(8500 gp per 100)
(170000 gp per backpack)
|| Creates a 3x3 area of Poison Fields.
||On PvP worlds, this spell is especially useful in player battles, as it achieves the same trapping effect as a fire bomb but does not kill low level characters looking to give players unjustified kills. The poison fields will last for 4:08.
You can use the Poison Bomb like Destroy field runes, because the fields dissapear and clean the fields that were there before.
See: Complete list of runes.