I don’t want to spoil her thunder

The host at a seminar was introducing the speaker and started to go into detail about some of her work.  She caught herself and then said this malaphor.  It is a mash up of “spoil the surprise (or ending)” (to ruin a surprise or ending by revealing it ahead of time) and “steal {someone’s) thunder” (when someone takes another person’s information or idea and uses it as their own).  Spoil and steal are both five letter words starting with s that probably led to the confusion.   A shout out to malaphor follower Ian for hearing this one and passing it on!