Max Roderick was in stitches after spotting the guard crouching down outside the store at shopping complex Liverpool One two weeks ago, eagerly awaiting his approach.
The 30-year-old filmed the guard, who was wearing his black security guard uniform, rocking back and forth as he peered through the shop window.
At one point the guard appears to make a false start but retreats back to his stalking zone temporarily.
Moments later he springs into action when an unidentified person – on crutches – begins to leave the store.
Keeping his eyes clocked on a suspected shoplifter, the guard then pounces forward to grab the person as they are about to leave the shop.
He then calmly ushers them back into the store while another man, believed to be shopping centre security, then runs in to help.
Max posted the video to social media last month where viewers have branded the eager guard “Spider-Man” and “Black Panther”.
Posting on Twitter, Max wrote: “How keen is that security guard” alongside several laughing emojis.
The video has gained over 6,500 likes and more than 500 retweets, as well as dozens of comments.
@Liverpoolcallin said: “The Black Panther strikes” alongside a GIF of the aforementioned Marvel superhero.
@kosang said: “Thinks he’s Spider-Man.”
@BandanaSavos said: “The guy’s on crutches. He isn’t getting very far!”
@Tattooeddadd said: “When the DJ announces the buffet is open.”
And @bigtjjimbo wrote: “Stealthy like a ninja!”
Speaking today, Max said: “I was doing a bit of Christmas shopping and noticed the guy with the bad leg on the rob, with the guard outside, and just started filming.
“After the video, I saw the security guard and a few others take the alleged thief away.
“It was quite funny though as the security guard and the alleged thief were laughing about it.
“The guard said to him: ‘You’re persistent I’ll give you that’ – so I’m guessing he’d probably been at it all day.
“I suppose it was a bit of an over-the-top reaction for a guy that was in crutches though.”
A spokeswoman at the Vans store today said: “Unfortunately, we’re not able to comment on this incident.”