Beetle walking upside down under water surface filmed in Australia 5 years ago
Snails dont have legs or limbs. And "walking" is a legged gait.
Limbless loco is a seperate story -https://en.m.wikipedia.org/wiki/Terrestrial_locomotion#Limbl...
Snails are pretty cool though with their mucus turning everyting around them friction free so they are badically ice skating. Have no clue what happens in water though.