gistfile1.php

<?php

class HackedDataQuery extends DataQuery {
  public function __construct($dataQuery) {
    $this->dataClass = $dataQuery->dataClass;
    $this->query = $dataQuery->query;
  }
  
  public function selectField($fieldExpression, $alias = null) {
		parent::selectField($fieldExpression, $alias);
	}
}

$list->alterDataQuery(function($query, $list) {
  $query = new HackedDataQuery($query);
  $query->selectField("YouJustMadeABaby", "Cry");
  return $query;
});