Is there a one-word synonym for "unwelcome surprise"?

Or anything along the lines of that (unpleasant surprise amounts to about the same thing). As in,

He/She found an unwelcome surprise waiting for them.

Unwelcome/unpleasant surprise would work in this context, but I feel I have used it too often, and need a change.

Thank you!

Solution 1:

Consider shock (Oxford Learner’s Dictionary):

[countable, usually singular, uncountable] a strong feeling of surprise as a result of something happening, especially something unpleasant; the event that causes this feeling

As you have a number of “unwelcome surprises” in your text I would reserve shock for the really bad ones. Here are some examples of actual use (my boldface):

Prokofiev had a shock waiting for him in Chicago regarding Oranges. After arriving in town on 31 October he wrote to Johnson requesting a meeting to settle their disagreement "peacefully." The letter he received in return on 2 November did not contain anything about an appointment, rather it bore the news that two weeks ago a telegram had been sent to him in France stating that Oranges had been canceled permanently.
[Stephen D. Press, Prokofiev’s Ballets for Diaghilev, 2006.]

Our return to England was homecoming in many ways, but there was a shock waiting for me when we reached the hotel at Rye. I was handed a cablegram: “Don't come home. I am in good hands. Mother.” The rest of the day was frantic. Heart Attack? Stroke? Paralysis?
[Doris McCarthy, Doris McCarthy: My Life, 2006.]

Solution 2:

Bombshell — (Cambridge)

a sudden and often unpleasant piece of news:

works well (he/she found a bombshell awaiting him/her), as do many other synonyms of shock (such as stunner, jolt, whammy), However, as Jacinto noted, they are best reserved for larger surprises.

Other words explaining the emotions or style of disrupt may be more helpful to exchange out more regular surprises, such as snafus, complications, or strangeness.