Flashlights disguised as glorified swords whose beams of light not only behave as if solid, and can cut through just about anything, but also emit no discernible heat until they come in contact with an object. And even then, they only project that heat onto the object.
Fire arms that emit condensed "pulses" of light; pulses that resemble elongated pellets; that seemingly generate more kinetic force and heat upon impact with a target than the pulse initially left the barrel with. And, as with the example above, seemingly generate no heat until contact with an object.
A series of omniscient, omnipresent beings that have supreme knowledge and control over all of existence but leave absolutely zero evidence of their meddling.
A transportation device that "disassembles" an object or creature down to the subatomic level, gathers these subatomic particles, transmits them over vast distances (with no loss of signal), and reassembles them in the exact right position and orientation; leaving no excess particles or energy behind.
A metallic ring that creates an extra-dimensional "tunnel" between two points in space-time, creating a "short cut", yet generates two-dimensional apertures and emits virtually no energy or radiation.
NASA thinking it advisable to both turn a team of oil-drillers into astronauts and to destroy an asteroid "the size of Texas" with a single, low-yield nuke drilled only 800 feet into said asteroid.
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Really, I could go on for hours. Literally hours of typing.
But in the end, who cares? It's fiction. It is, by defintion, unreality. The only time ridiculous "things" in fiction should be of any concern is when they either break the rules of the fictional piece they're in or if the very concept of the "thing" doesn't jive with the logic of the story-verse.