Melibe viridis hunting. Alien like creature is invasive species

Melibe viridis is a sea slug that roams the bottom using it hood like mouth to scoop up crustaceans.
It is native to Indo-pacific areas but has made the journey through Suez canal to now be in Mediterranean.
Large number can be seen. But quite difficult to spot even though they are quite large for sea slugs because partly transparent and other colours match their surroundings.