It's a Mammal with a Duck Bill: Mammals are typically known for having fur, giving birth to live young, and nursing them with milk. Platypuses fit all those criteria. But they also have a flat, rubbery bill that looks and functions like a duck's, which is unusual for a mammal.
It Lays Eggs: While most mammals give birth to live young, the platypus lays eggs like reptiles and birds.
It has Venomous Spurs: Male platypuses have venomous spurs on their hind legs, which they use for defense. This is unique amongst mammals.
It's Electroreceptive: Platypuses have electroreceptors in their bill, which allows them to detect the electrical fields generated by prey. This is similar to sharks and other aquatic creatures.
Its Evolutionary History: The platypus is a member of the monotremes, a group of mammals that diverged from other mammals very early in their evolutionary history. This means they have retained some primitive features, making them appear even more unique.
In Summary: The platypus defies easy categorization. It's a mammal with a duck bill, lays eggs, has venomous spurs, and can sense electricity. This unique blend of features makes it a true evolutionary marvel and an incredibly fascinating creature.