This is my first plugin. I will start by confessing i'm a total n00b at coding, so... this is just a modification of scorp's crossbow trail plugin (inspired on Trailball by raziEil) that he was kind enough to develop for me some months ago.
What I did was to just change the entity to attach trails to, which is the npc_grenade_frag.
I also added a new ConVar named sm_grenadetrail_material
, which allows you to change the material of the trail instantly.
After installing the plugin and loading it for the first time, it will generate a config file in cfg/sourcemod
Note: I am also looking for a way to remove the original npc_grenade_frag red trail. Suggestions are welcome! =)