Scene with everything capsized involves unknown danger to shipping (6)
I believe the answer is:
scylla
'danger to shipping' is the definition.
(I've seen this before)
'scene with everything capsized involves unknown' is the wordplay.
'scene with' becomes 'sc' (I can't justify this - if you can you should give a lot more credence to this answer).
'everything' becomes 'all' (all things).
'capsized' is a reversal indicator.
'involves' is an insertion indicator.
'unknown' becomes 'y' (algebra).
'all' written backwards gives 'lla'.
'sc'+'lla'='sclla'
'sclla' going around 'y' is 'SCYLLA'.
Can you help me to learn more?
(Other definitions for scylla that I've seen before include "Charybdis counterpart" , "Rock, across from 21" , "danger to shipping" , "legendary menace in Med" , "Artificial cave" .)