A gas spore, e , can be dangerous for the unprepared. They act as a "living mine" exploding in a small radius when killed, therefore likely to kill your pet if it is too close. The best strategy when faced with a gas spore is to step back and cast offensive spells, or shoot the gas spore with arrows, darts, or throwing rocks and junk weapons at them. Sleep spells will bounce off them.
You are responsible for any damage done by a gas spore explosion you cause. This means that if you cause a gas spore to explode, killing your pet, it counts as though you killed the pet. It also means that if you cause a gas spore to explode next to a peaceful monster, it will become angered. Note that angering peaceful humans throughout the dungeon is generally a Bad Idea.
If, however, no nearby pets or other peaceful entities are nearby, and you have HP above 24 and/or a good AC, it might be best to dispatch of the spore with melee attacks, especially if you don't have a ranged weapon.
Encyclopedia entry Edit
The attack by those who want to die
-- this is the attack against which you cannot prepare a perfect defense.