The recently-released "Story Featurette" for Marvel Studios' first Disney+ series, WandaVision, subtly heralds the Marvel Cinematic Universe debut of a fan-favorite family friend from writer Tom King and artist Gabriel Hernandez Walta's critically-acclaimed Marvel Comics title The Vision.

The featurette delves into various aspects of WandaVision, including the sitcom-esque nature of its early episodes, which were even filmed before a live studio audience. Towards the end of the video, however, a blink-and-you'll-miss it reference to Sparky, the dog created by Vision in the comics to serve as his family's pet.

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During a brief sequence where Elizabeth Olsen's Wanda Maximoff/Scarlet Witch and Paul Bettany's Vision are seen staring each other down, both floating above the ground, a dog house can be seen beneath Vision's feet. Above the dog house's door is a name plate that simply reads, "Sparky."

Created by King and Walta, Sparky first appeared in 2016's The Vision #6. A green, synthezoid dog, Sparky was created by Vision in an attempt to reunite his family after the Grim Reaper/Eric Williams' corpse was found buried in their backyard. Vision's wife, Virginia, later killed the dog in a rage. However, Tony Stark and Scarlet Witch managed to resurrect Sparky, at which point he returned to Vision's daughter Viv. Sparky went on to appear alongside Viv after she made the jump to Marvel Comics' Champions series.

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Marvel Studios boss Kevin Feige previously teased Sparky's involvement in WandaVision during CCXP in December of 2019. When Feige was asked if the Disney+ series would take inspiration from King and Walta's The Vision, he replied, "Partially, yes... If you know that comic, you might meet Sparky the Dog at a certain point in that series, but it's only just inspired by that series and goes into a different direction."

WandaVision premiered its first two episodes on Disney+ on Friday, Jan. 15 to kick off Phase Four of the MCU. Per the series' official synopsis,

Marvel Studios’ “WandaVision” blends the style of classic sitcoms with the Marvel Cinematic Universe in which Wanda Maximoff (Elizabeth Olsen) and Vision (Paul Bettany)—two super-powered beings living their ideal suburban lives—begin to suspect that everything is not as it seems. The new series is directed by Matt Shakman; Jac Schaeffer is head writer. Debuts on Disney+ this year.

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Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. New episodes air Fridays on Disney+.

Source: YouTube\Marvel Entertainment, via The Direct