Captain Planet and the Planeteers (1990)

Season 2: Episode 19

The Planeteers return to Kwame's homeland, Africa, to investigate strange happenings with cattle that was reported by his long-time friend and brother figure, Dr. Mabutu. Little do they know, Dr. Blight is there, scheming to convince a tribe leader (also a friend of Mabutu) to allow the injection of a serum that turns bulls into super steers in order to resolve their meat supply woes. Not only does this threaten the condition of the land, via excessive grazing, but the serum causes awkward side effects, which eventually does wear off. The Planeteers, with a hand from Captain Planet, manage to rid the land of Blight and MAL.