With stealth, some regressive amoebae kill, eerily (3-4)
I believe the answer is:
eel-like
'with stealth some regressive amoebae kill eerily' is the definition.
I can't judge whether this definition defines the answer.
'some regressive amoebae kill eerily' is the wordplay.
'regressive' says the letters should be written backwards (to regress is to go backwards).
'some' says the answer is hidden in the clue (some parts of the word are used).
'ekillee' can be found hidden inside 'amoebae kill eerily'.
'ekillee' reversed gives 'EEL-LIKE'.
Can you help me to learn more?
(Another definition for eel-like that I've seen is " writhing and slippery?".)