amoeba-brained, adj. — Green’s Dictionary of Slang

amoeba-brained adj.

[the tiny size]

(US) very stupid.

1940		Maryville Dly Forum (Maryville, MO) 9 Jan. 4/3: We should back the boss into a corner and say, ‘why you, hunky, amoeba-brained idiot, get a load of this’.
1953		Northwestern Lutheran 40-41 37: Read Genesis 4, 16-24 and 6, 4 and you will not find evidence of a low-brow, amoeba-brained, crudely formed man, but rather mental giants [...] though corrupted by sin.
1965		E. Bombeck At Wit’s End (1979) 47: And-so’s-your-amoeba-brained-wife.
1972		R.A. Wilson Playboy’s Bk of Forbidden Words 21: You [...] amoeba-brained asshole!
1994		Zap mag. Aug. n.p.: When it comes to dealing with creepazoid, mutant, amoeba-brained little brothers, you’ve come to the master!
2000		trashcity.org Mar. 🌐 It always amazes me that Browns is so good, when the Griffin, run by the same people, is such a pit; mind you, not having the latter’s amoeba-brained DJ is a big plus.