Tentacled creature regularly painted with submariner in its grip (7)
I believe the answer is:
anemone
'tentacled creature' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'regularly painted with submariner in its grip' is the wordplay.
I cannot quite understand how this works, but
'submariner' could be 'nemo' (Captain Nemo in 20,000 Leagues Under the Sea) and 'nemo' is found within the answer.
The remaining letters 'ane' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for anemone that I've seen before include "Bright flower or sea plant" , "Sea creature, also flower" , "climbing plant" , "Windflower - sea creature" , "Tentacled sea dweller, flower" .)