Explanation: After the illegal occupation of the Palestinian West Bank, Israel launched the Battle of Karameh, in which Israeli forces assaulted Palestinian guerillas who were taking refuge in Jordan, assuming that the military of Jordan would be too anxious about Israeli reprisals to risk interfering, and that the Palestinian guerillas would be easily scattered by a 'proper' military force.
They were wrong. The Jordanian Army lent significant support to the Palestinians, particularly through artillery fire, and the Palestinian fedayeen resisted ferociously, resulting in significant Israeli casualties before Israel was forced to withdraw.