The speaker was talking about an incident involving some students on campus and said to a colleague, “they’re getting ready to lower the bomb on them.”  This is a nice mashup of “lower the boom” (to scold or punish someone) and “drop the bomb” (to reveal startling information).   Bombs go BOOM so there you go.   A big thanks to frequent contributor Martin Pietrucha who unintentionally blurted this one out.

If you enjoyed this one there are many more just like it in my malaphor book, “He Smokes Like a Fish and other Malaphors”, available on Amazon now!  Makes a perfect bathroom read.