intrusive

adj

1. Tending to intrude; doing that which is not welcome; interrupting or disturbing; entering without permission or welcome.

   “Did it ever cross your mind that he might find all those questions you ask intrusive?”

2. Of rocks: forced, while in a plastic or molten state, into the cavities or between the cracks or layers of other rocks.
3. epenthetic
4. Designating a type of collection in which each item keeps track of what collection it is in, rather than the more conventional approach of a collection keeping track of what items it contains. An intrusive collection does not "own" its contents and a single item can be part of multiple intrusive collections.

   “an intrusive linked list”

noun

1. An igneous rock that is forced, while molten, into cracks or between other layers of rock