if you mean CUSTOM NAME only not CUSTOM MOB this script will help you
- script monster_script -1,{
// "Poring (1002)" spawns on random coordinates
// Fake Name is "Kill Me!"
monster .map$,0,0,"Kill Me",.monster,.monster_count,strnpcinfo(0)+"::OnMobKilled";
// Event Configurations
OnInit:
set .monster,1002; // Mob ID
set .monster_count,1; // Mob Count
set .map$,"prontera"; // Possible map
set .prize,1000; // 1000 is the item ID
set .prize_amount,1; // Prize quantity
end;
OnMobKilled:
getitem .prize,.prize_amount; // Prize of the Killer
announce "[ "+strcharinfo(0)+" ] has killed ["Kill Me!"] on ["+.map$+"]",bc_map; // Broadcast the killer on current map;
monster .map$,0,0,"Kill Me",.monster,.monster_count,strnpcinfo(0)+"::OnMobKilled"; // The Mob will spawn again
end;
}