The mask has been described as "carnivorous" since it gladly eats, for example, earthworms.
Even though we have seen that the flatworm does not survive being frozen, it can almost always find sheltered hiding places where it survives, says Cajza Eriksson at the Skåne County Administrative Board to SVT News Skåne.
She coordinates the County Administrative Board's work against invasive species and is concerned that the influx of flatworms to Sweden via plant imports is greater than expected.
When we have tested feeding it, we have seen that it really likes earthworms, which is problematic since it can reduce soil fertility in the long run, she says to SVT.