German A1 Level Question

The sentence 'Er isst einen Klumpen Schokolade.' correctly uses 'Klumpen' to describe a lump of chocolate. 'Ich spiele mit einem Klumpen' is incorrect because you typically don't play with a lump. 'Der Klumpen singt schön' and 'Sie trinkt den Klumpen' are incorrect as lumps cannot sing or be drunk.