Create circles with river plant that's toxic (8)
I believe the answer is:
mandrake
'plant that's toxic' is the definition.
I can't tell whether this definition defines the answer.
'create circles with river' is the wordplay.
I cannot quite see how this works, but
'with' could be 'and' (I've seen this before) and 'and' is located in the answer.
'river' could be 'r' and 'r' is located in the answer.
'create' could be 'make' ('make' can be a synonym of 'create') and 'make' is found within the remaining letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for mandrake that I've seen before include "May apple" , "Poisonous plant once thought to have magical powers" , "Eurasian plant with purplish flowers" , "Poisonous plant with large forked root" , "Poisonous plant or cartoon magician" .)