Teenage Mutant Ninja Turtles, Season 2

Donatello:
(Narrating) They say the sea is the last unexplored frontier on Earth, and I would have to agree. Because what we're looking at is one of the strangest things I've ever seen. And that's saying a lot coming from five foot tall talking turtle. What started out as a test run of the new shell-sub quickly turned into a discovery of bizarre proportions. Of course, all exploratory missions should be undertaken with great caution; If you venture into new territory unprepared, it can really come back to bite you in the shell.