public OnEntityCreated(entity, const String:classname[])   
{   
   if(StrEqual(classname, "weapon_smg1"))   
   {   
    CreateTimer(0.01, Timer_Entity, entity);   
   }   
}   

public Action:Timer_Entity(Handle:timer, any:entity)   
{   
   new client = GetEntPropEnt(entity, Prop_Send, "m_hOwnerEntity");
   if(!IsValidEntity(client)) return Plugin_Stop;
     
   if (client > 0 && client <= MaxClients)   
   {   
    // Здесь должен быть эффект
   }
return Plugin_Stop;   
}

createSprite(client)
{
   env_sprite[client] = CreateEntityByName("env_sprite");
   if (!IsValidEntity(env_sprite[client]) && (env_sprite[client] != 0))
   {
    return;
   }
   new Float:origin[3];
   GetEntPropVector(client,Prop_Send,"m_vecOrigin",origin);
   origin[2] += 80.0;
   DispatchKeyValueVector(env_sprite[client],"origin",origin);
   DispatchKeyValue(env_sprite[client],"model","materials/Sprites/bluelight1.vmt");
   DispatchKeyValue(env_sprite[client],"rendermode","1");
   DispatchKeyValue(env_sprite[client],"spawnflags","1");
   DispatchKeyValue(env_sprite[client],"scale","0.3");
   DispatchSpawn(env_sprite[client]);
   SetVariantString("!activator");
   AcceptEntityInput(env_sprite[client],"SetParent",client);
}

#include <sourcemod>
#include <sdktools>

public OnMapStart()
{
  PrecacheModel("sprites/bluelight1.vmt");
}

public OnEntityCreated(entity, const String:classname[])
{
  if(StrEqual(classname, "weapon_smg1"))
  {
   CreateTimer(0.01, Timer_Entity, entity);
  }
}

public Action:Timer_Entity(Handle:timer, any:entity)
{
  new client = GetEntPropEnt(entity, Prop_Send, "m_hOwnerEntity");
  if(!IsValidEntity(client)) return Plugin_Stop;
   
  if (client > 0 && client <= MaxClients)
  {
   Void_AttachTrail(client);
  }
  return Plugin_Stop;
}

void:Void_AttachTrail(client)
{
         new g_iEntity[client];
         g_iEntity[client] = CreateEntityByName("env_spritetrail");
         if(g_iEntity[client] > 0 && IsValidEdict(g_iEntity[client]))
         {
   
                 new Float:g_fOrigin[3], String:g_sName[MAX_NAME_LENGTH];
                 GetClientName(client, g_sName, sizeof(g_sName));
                 Format(g_sName, sizeof(g_sName), "Trails_%s", g_sName);
         
                 DispatchKeyValue(client, "targetname", g_sName);
                 DispatchKeyValue(g_iEntity[client], "parentname", g_sName);
                 DispatchKeyValue(g_iEntity[client], "lifetime", "1.5");
                 DispatchKeyValue(g_iEntity[client], "endwidth", "0.1");
                 DispatchKeyValue(g_iEntity[client], "startwidth", "5");
                 DispatchKeyValue(g_iEntity[client], "spritename", "materials/sprites/bluelight1.vmt");
                 DispatchKeyValue(g_iEntity[client], "renderamt", "255");
                 DispatchKeyValue(g_iEntity[client], "rendercolor", "255 0 0");
                 DispatchKeyValue(g_iEntity[client], "rendermode", "5");
   
                 DispatchSpawn(g_iEntity[client]);
   
                 new g_fTrailHeight;
                 GetClientAbsOrigin(client, g_fOrigin);
                 g_fOrigin[2] += g_fTrailHeight;
                 TeleportEntity(g_iEntity[client], g_fOrigin, NULL_VECTOR, NULL_VECTOR);
                 SetVariantString(g_sName);
                 AcceptEntityInput(g_iEntity[client], "SetParent");
         }
}