The sound fx for the read-out printer in Wo Fat's sensory deprivation chamber are the same as the communicators in Star Trek TOS, and the sound made when tilting the table is the same as Enterprise (et al) sliding doors.
Not only was this the first appearance of arch-nemesis Wo Fat, it also marked the first appearance of recurring character Jonathan Kaye.
This episode was remade exactly 50 years later as the Season 9 season opener of the new Hawaii 5-0 series. Alex O'Loughlin was placed in the sensory deprivation chamber, the same way that Jack Lord had been.
Although not broadcast on television until September 20, 1968, Cocoon was actually filmed a year earlier in late 1967. The film was premiered for a select audience at Honolulu's Royal Theater on February 19, 1968. Cocoon was also screened in early 1968 for a test audience in New York, who reportedly disliked actor Tim O'Kelly in the role of Danny 'Danno' Williams. For the series, Danno was recast with James MacArthur. Series producer Leonard Freeman had recently worked with MacArthur on the Western film Hang 'Em High (1968).
Actor Jack Lord pays homage to his earlier series Stoney Burke (1962) when undercover as a workman wearing a denim shirt and neckerchief, the standard garb he wore as rodeo rider Stoney.