Mash (citation) is a software for fast genome distance estimation and contamination screening using the MinHash algorithm. It supports two different commands:

Mash Distance
Rapid estimation of the distance between genomes
Used in SeqSphere+ for rapid species identification and automatic project choosing in pipeline
Mash Screen
Rapid screening of sequence containment in (meta-)genome data
Used in SeqSphere+ for species contamination check

For both, SeqSphere+ comes with a Mash reference database that contains a collection of all complete genomes or chromosomes from prokaryotic entries represented in NCBI Genomes, filtered by taxonomic reliable genus and species information.