Crazy cows...

gistfile1.txt

var entities = [],
  entityType = null,
  entitytypes,
  t;
if (__plugin.bukkit) {
  entityType = org.bukkit.entity.EntityType;
}
if (__plugin.canary) {
  entityType = Packages.net.canarymod.api.entity.EntityType;
}
entitytypes = entityType.values();
for (t in entitytypes) {
  if (entitytypes[t] && entitytypes[t].ordinal) {
    entities.push(entitytypes[t].name());
  }
}

command('spawns', function (parameters, sender) {
  if (!isOp(sender)) {
    echo(sender, 'Only operators can perform this command');
    return;
  }
  var location = sender.location;
  if (!location) {
    echo(sender, 'You have no location. This command only works in-game.');
    return;
  }

  var world = location.world || sender.world,
    type = ('' + parameters[0]).toUpperCase();
  if (__plugin.bukkit) {
    world.spawnEntity(location, entityType[type]);
  }
  if (__plugin.canary) {
    for (i = 0; i < parameters[1]; i++) {
      var Canary = Packages.net.canarymod.Canary,
        entity = Canary.factory().entityFactory.newEntity(entityType[type], location);
      entity.spawn();
      entity.motionY = 3;
    }
  }
}, entities);