Created by writer Kelly Thompson and artist Daniele di Nicuolo, the character first appeared in West Coast Avengers (vol.

[1][2][3] Jeff is the pet landshark (legged shark) of the superheroes Gwen Poole and Kate Bishop, and has also been cared for by Wade Wilson and Elsa Bloodstone.

One of the landsharks drawn by Caselli caught Thompson's eye, so she created a character, drawing on the shark imagery and her own pet cats.

[8][1][9] Following a universally positive internet reception, Jeff consequently appeared in the rest of the run of West Coast Avengers.

#1 was released in print in March 2023; this one-shot issue collects the short stories originally published in the digital Infinity Comics format.

[25][26] Jeff was "venomized" as part of Marvel's 2023 Summer of Symbiotes event in the short story "The Rhythm of the Night" written by Thompson and drawn by Gurihiru.

[30] He also appeared in Marvel Rivals Infinity Comic (2024), a six-issue limited series by writer Paul Allor and artist Luca Claretti.

[35] Nao Fuji (artist of Marvel Meow) also did a variant cover, for Shang-Chi and the Ten Rings #4 (October 2022), featuring Jeff.

[36] When the West Coast Avengers led by Kate Bishop defeated the West Coast version of the Masters of Evil that MODOK Superior was a part of, MODOK Superior's former employee and nemesis Gwen Poole found and adopted a baby land-shark, naming it Jeff after a kitten of the same name Gwen had adopted earlier in the series but who she had to give up.

[37] Gwen, a real world being aware of the fictional comic book nature of the Marvel Universe after being transported there, becoming concerned so many titles featuring her to have been cancelled, in an attempt to secure a better future for Jeff, briefly entrusts him to Wade Wilson, only for his title to be promptly cancelled as well,[8][10] and for Elsa Bloodstone to briefly look after Jeff.

Here at Multiversity, it quickly became a running gag in the pages of Saturday Morning Panels just how much we all love that little land shark".

[11] Susana Polo of Polygon highlighted how the issue isn't more complicated than "Jeff gets into some shenanigans, finds a cute way out of them" – it has Gurihiru's "charming art" and Thompson's writing is "Sunday Funnies simple".

#1 is a welcome respite of aesthetically pleasing fun, sweetness and mischief, putting a spotlight on a minor character whose appeal cannot be understated.

#1 a grade of 4.5 out of 5, writing, "In addition to splendidly told strips, the full comics page provides plenty of space for background gags that are bound to absorb readers with nods to beloved characters.

[47] Pleasant opined that "between [Thompson's] story and Gurihiru's artwork, we get the tale of a happy little land shark who can get into trouble, but mostly just wants to have fun, be loved, and eat all the food he can find.

[52] Kazemi commented that due to the issue's "great panels, there's never a moment where a reader is questioning what's happening or how Jeff is feeling".

[54] Marshall highlighted that in play they enjoy Jeff's "toe beans, the way he hums menacingly when he submerges beneath the ground, his reload animation that has him flip on his back and snack on a tasty fish".

[55] He highlighted that Jeff's "destructive power contrasted with his cute, unassuming demeanor has made him the center of so many jokes in the game's community just days after launch".

[55] Apsey similarly noted that Jeff has become an "instant favorite for his adorably menacing antics" and an "internet darling".

3) #7 on eBay increased following a spike in "Jeff's popularity" due to "his prominent appearance in the Marvel Rivals video game".