If you find pink eggs in your garden, you should act quickly. The distribution of the genus Pomacea is prohibited within the EU.
Apple snails are popular with aquarium owners as algae-eating cleaning crews. Some people circumvent the ban so that the animals can escape into the environment via the garden pond. Accidental importation via eggs on aquarium and pond plants is also possible. It may currently be too cold for the animals to spread massively here, but climate change could soon make it possible.