Encroach

[Sarah]

To enter by gradual steps or by stealth into the possessions orrights of another; to trespass; to intrude; to trench; -- commonlywith on or upon; as, to encroach on a neighbor; to encroach on thehighway.No sense, faculty, or member must encroach upon or interfere with theduty and office of another. South.Superstition, . . . a creeping and encroaching evil. Hooker.Exclude the encroaching cattle from thy ground. Dryden.

[Sarah]

approaching or intruding, especially in a gradual or sneaking way; advancing beyond customary limits.

[Sarah]

Basically, to creep.