Hey, I'm new to modding and this forum. I've been working on a mod to ramp up the difficulty of many of the mobs. The way my mod currently works is by adding effects upon firing the LivingSpawnEvent. I want to be able to reduce the fuze time on the creeper, I've found it in the source code but I have no idea what to do with that information. Thanks! Also, if you could address how to make the explosion larger that'd be sweet, too!

You would need to modify fuseTime and explosionRadius within CreeperEntity using reflection.

@ChampionAsh5357Ok.  I'm new to this, what is reflection? And where would be the best place to learn how to use it? Thank you so much!

You need to learn some more Java. Forge does provide an easy access to reflection via ObfuscationReflectionHelper. Note: you will need to locate the unmapped names of all the fields you would like to modify.