Lileep is a somewhat plantlike Pokémon with eight dark-tipped, pink petal-like tentacles protruding from an opening on top of its head. Inside the pitch-black opening are two glowing, yellow eyes. The remainder of its head is purple with yellow eyespots resembling targets. The head is connected to the body through a yellow stem. The body itself is purple and semi-spherical. Four stubby roots anchor this Pokémon firmly to the rocks of its home on the sea floor.
In ancient times, it lived in warm seas. It waves its tentacles around to disguise itself as seaweed to attract prey, which is swallowed whole after being entangled. Lileep has been extinct for 100 million years, but specimens can be revived from Root Fossils.
Lileep may be based on crinoids (also known as sea lilies), extant marine animals. Crinoid fossils are particularly abundant, possibly inspiring Lileep's status as a fossil Pokémon. Its tentacles may be based on those of the sea anemone.
Lileep may be a combination of lily and deep, sleep, creep, or peep.
Lilyla may be a combination of lily and possibly lila (Spanish for lilac, referring to its purple color).