"It's called a 'Mouse Hole.' Cuts through anything, really." ― Leo Fitz [src]
Mouse Hole is a laser-cutting tunnel boring device capable of cutting through almost any material. It was created by S.H.I.E.L.D. agent Leo Fitz, although it was not mass-produced and instead kept for use by high-ranking agents.
"I designed it a year ago and submitted it for testing, but it never reached distribution." "Top agents always hog the good stuff." ― Leo Fitz and John Garrett [src]
Leo Fitz, the Mouse Hole never went to production for field agents, as S.H.I.E.L.D. chose to keep it exclusive for higher ranking agents.
"Best bet to save her, use the ventilation system to get above the sit room. Drop down using Fitz's sweet little Mouse Hole, and put two bullets though Victoria Hand's heart." ― John Garrett [src]
Nick Fury escapes from his destroyed vehicle Nick Fury used a Mouse Hole to escape from his destroyed vehicle during an assassination attempt by the Winter Soldier.
Maria Hill later used a Mouse Hole to free Captain America, Black Widow and Falcon from STRIKE operatives.
Leo Fitz uses a Mouse Hole to lead the team's escape
Leo Fitz used a Mouse Hole to affect the escape of his team from the Bus when Victoria Hand sent a kill-squad aboard the plane, falsely believing that Phil Coulson and his team were HYDRA agents.
Lance Hunter got stuck in a S.H.I.E.L.D. SUV after it was flipped by Carl Creel. Melinda May planned to use the Mouse Hole to get Hunter out of the car, but he told her to continue the chase for Creel. Before leaving, May gave Hunter the Mouse Hole which he used to escape from the SUV. After escaping he was caught by soldiers from the United States Armed Forces.
The city that matched the
Words of Creation was found underground. Alphonso Mackenzie used the Mouse Hole as a cutting tool to make an opening to a 100 foot shaft leading down to its entrance.
alternate 1976, the Chronicoms kidnapped John and Lilla Mackenzie to ensure that Project Insight was launched ahead of time without S.H.I.E.L.D. interfering.  Alphonso Mackenzie used the Mouse Hole to cut through the wall of cell where John and Lilla were being held.
In chronological order: