Made in Hong Kong this snake-like concept car has a metal body, base, and exposed engine with a plastic interior.

 a. yellow, metal base, chrome int., green spots on top, uh. Speed Demons $5 – 10
 a2. yellow, as a, uh, Mal. Speed Demons 5 – 10
a3. yellow, as a, uh, Mal. #155 1 – 3
a4.  yellow, as a, ho, Mal. #155 (1992) 6 – 15
 a5. yellow, as a, sp5, Ch. Snake Pit playset (1998) 4 – NA
 b. purple, metal base, neon orange crackles, orange pipes, engine and int., uh, Mal. Krackle Car #281 (1995) 3 – 5
 b2. purple, as b, sp7, #281 (1995) 3 – 5
 b3. purple, as b, silver metal base, uh, #281 (1998) 3 – 5
 c. mustard yellow, metal base, black, red, and silver design on top, sp5, Ch. #598 (1998) 2 – 4
 d. mf green, metal base, chrome int., red eyes, black and green design on top, pr5gn, Mal. #130 (2006) 2 – 3
 e. mf brown, as d, black eyes, black and gold design, pr5cp, Mal. #130 (2006) 2 – 3
e2. mf dk. brown, as e, pr5cp, Mal. #130 (2006) 2 – 3
 f. orange, metal base, chrome int., black and silver flame stripe on top, pr5or, Mal. multi-pack (2011) 2 – NA
 g. candy blue, metal base, chrome int., orange and white design on top, pr5or, Mal. Mystery Models intl. #47 (2013) 5 – 10

Bonus Picture: Hong Kong / Malaysia casting difference.