escalate
v.v. to become more serious, intense, or dangerous. You use this when a small problem or argument grows into a much bigger one.
v. to increase rapidly in intensity, magnitude, or severity. Often used to describe the progression of conflicts, prices, or military engagements.
The small argument began to escalate into a loud fight.
The manager stepped in to resolve the customer's complaint before the situation could escalate further.
Diplomatic efforts failed to prevent the border skirmish from escalating into a full-scale regional conflict that drew in several neighboring nations.
Back-formation from escalator.
The verb can be used both transitively (to escalate something) and intransitively (something escalates).
The problem was escalated by itselfThe problem escalatedWhen a situation grows on its own, use the intransitive form without 'be' or 'by'.