A character that is holding or interacting with an object significantly bigger than normal relative to their size. Since it is defined relatively, minigirls and miniboys count, but only when directly interacting with a full-sized object.
If the object is a weapon, it may also be a huge weapon (though not all huge weapons count as oversized objects; some are supposed to be that big.)
The following tags implicate this tag: large_syringe (learn more).