The most common and most likely answer to this crossword clue is the 8 letter word SEASHELL
I've seen this crossword clue in The Guardian
S
E
A
S
H
E
L
L
More clues leading to the result SEASHELL
- What mollusc inhabits ocean’s lower regions?
- Home for hermit in Home Counties — like Hades
- He sells a mobile home by the coast, perhaps
- Unusual hassle accommodating European learner
- Cockle maybe from south, all she’s flogged
- Go outside when he finds a beach relic
- Reportedly receives severe censure when it’s found on the beach
- Hard evidence of life in realms of Neptune and Pluto
- One thing female tries to dispose of on beach? It’s hard to say!
- Prosperous region as horrible place for one stranded by the coast?
Buddy explains!

The straight part
We know that "Hard evidence of life" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hard evidence of life = seashell.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SEASHELL mean?
SEASHELL noun- The empty shell of a marine mollusk
- A very light pink colour, like that of some seashells.
- Of a very light pink colour, like that of some seashell.