"Have You Seen This Snail?" received mostly positive reviews from television critics. Tom Shales of "The Washington Post" called the episode deeply hilarious and described the plot as a "bittersweet riot". He drew attention to how the story is similar to the plot of "Dumped", an earlier episode in which Gary deserted SpongeBob. David Johnson of the DVD Verdict positively reacted to the DVD release of the episode and said "I'm not sure what to say, here. Mr. Squarepants is so ridiculously popular, this disc will most definitely sell itself." Aida Ekberg of Yahoo! Voices ranked Amy Poehler on her "Top 10 "SpongeBob SquarePants" Guest Stars" list and said "I'm surprised more comedians haven't been guest stars on SpongeBob. Amy Poehler does a great job with her creepy grandma voice, playing pure evil masked behind plate after plate of chocolate chip cookies." Paul Mavis of DVD Talk loved the scene "When Gary realizes he has to escape from her crushing love (which equals constant overeating) or die like the other snail shells he finds" He said "it's both funny and rather touching."