Assertion: narwhal's tusk | /r/SimilarTo | a unicorn's horn
Facets:
Source sentences:
text: Narwhals are medium-size marine mammals known for their characteristic tusk that resembles a unicorn's horn.
text: Narwhals are sometimes called “the unicorns of the sea,” because they have a large tusk that grows on their heads that looks like a unicorn’s horn.