Right at the beginning of "The Infiltration", two MAD agents come close to killing Gadget by dragging him behind their boat, forcing him to crash into various other boats and objects, before trapping him in a cage underwater. He only escapes when he manages to make his laser-finger function beneath the surface to cut the bars out.
Dr Claw's plan in the episode is to have master disguise artist Presto Changeo masquerade as the presumably-dead Gadget to infiltrate a security conference. He comes close enough to succeeding by actually being present at the start of the meeting before the real Gadget finally bursts into the room.
Gadget: If I don't find him soon, the safety of the free world could be in jeopardy.
Changeo manages to use his Gadget disguise to convince a security guard to imprison Penny, claiming that she is Changeo.
There's a lot of potential for Fridge Horror in Gadget's robotics, but occasionally it's less implicit than usual.
For example, in "Magic Gadget," the second-season premiere episode. In their attempts to murder Gadget, the Great Wambini (stage magician cum ruthless M.A.D. agent) and his flunkies in turn transfix him with swords, drown him, and finally cut him in two at about mid-stomach height, trying to effect a Rasputinian Death. Gadget, of course, survives everything with only mild discomfort, and continues his investigation in his usual bumbling fashion — both halves of him. Wambini and company (and Brain) are, naturally, horrified.
Gadget himself is more annoyed by this, muttering that he has to "pull himself together" as he literally does so.
From Season 2, "Gadget and Old Lace". The villains hired by Claw to get rid of Gadget are two cute but murderous old ladies, Sadie and Viola, and their ward Franklin, a mute giant wearing a boys' sailor suit several sizes too small, who immediately starts digging a fresh grave for Gadget among all the tombstones in the family garden...! Without Gadget's comedic antics, this would be pure horror material. As it stands, it's still disturbing, and also features one of the most graphic (and closest to successful) attempts on Gadget's life throughout the series. (It involves electrocution.)
