Pseudo-sciency technobabble mumbo jumbo...
Believe it or not, I suspect some folk found that a bit confusing.
Do what now?
So, a "large spider" is roughly equivalent to a Small Monstrous Spider in 3E.
Agreed, and I would like to allow for them advancing to a BIG size, simply because I find the idea of Giant Spider Bombs highly amusing.
Yes, that is amusing.
I'm wondering whether we could use some of the Explosive special attack of my Gumberoo homebrew:
Explosive (Ex): Whenever a gumberoo takes damage from fire or electricity it needs to make a Fortitude saving throw against a DC equal to 10 plus the hit points of fire and electrical damage inflicted. Failure results in the gumberoo expiring in a frightful explosion that inflict 6d6 points of bludgeoning damage and 6d6 points of fire damage to everything within a sixty foot radius burst, with a DC 19 Reflex save to take half damage. The saving throw is Con-dependent.
We probably can do just that.