The application of methodologies for building ontologies has improved the ontology quality. However, such a quality is not totally guaranteed because of the difficulties involved in ontology modelling. These difficulties are related to the inclusion of anomalies or worst practices in the modelling. Several authors have provided lists of typical anomalies detected in ontologies during the last decade. In this context, our aim in this technical report is to describe OOPS! (OntOlogy Pitfalls Scanner!), a tool for pitfalls detection in ontology developments