Whelks definitely move slower than taters too (or is that cockles I'm thinking of - probably, with bacon and laverbread! There's a conk for you!).

Bananas are a type of herb, and the trees can walk. This is a a good statement to use to make a whelk feel stupid (it won't work with mussels because they're immune to old gastropod mind tricks, as I'm sure any one with a byssal beard would tell you).

But there - I'm getting above my station again, making molluscs feel inferior because they've only got one foot and and their alimentary canals are too simple to digest the information. I'll shut reet up.