If you find pink eggs in your garden, you should act quickly. The apple snail genus (Pomacea) is an invasive species that causes massive damage to many plant species.
Apple snails prefer to stay near bodies of water such as rivers or streams, or in ponds. In Germany, the distribution of the genus Pomacea is prohibited within the EU; the freshwater snails may neither be sold nor passed on from one aquarium owner to the next. It may currently be too cold for the animals to spread massively here, but climate change could soon make it possible.