Animals do not avoid, and perhaps seek, environments that result in their death. In the case of C. elegans, this behavior is exemplified by animals that tend to crawl off the plate.
Premature lethality during the adult stage. When applied to large-scale RNAi screens in C. elegans, this phenotype is present in at least 10% of analyzed worms, or at least 30% in the case of rrf-3 perturbed background.