«فَتَحُوهَا الْفِيرَانْ وِقْعُوا فِيهَا التِّيرَانْ»

The image is of mice burrowing in the earth and leaving holes, and of heavy bulls (التيران, a colloquial plural) that later stumble into those holes and fall. The small creatures make the opening, but the large ones pay for it, because their weight and size turn a trivial tunnel into a real hazard.

Applied to people, the saying describes mischief or mistakes made by the young or the insignificant that end up hurting, or being charged to, those who are older or more important. Those held accountable did not start the trouble and are not at fault, so the outcome feels unfair.

Fits situations where children, juniors, or subordinates cause a problem and parents, elders, or superiors end up facing the damage or the blame. It can be said with resignation or as a gentle rebuke to those responsible.