SB 10.88.23

sa tad-vara-parīkṣārthaṁ
 śambhor mūrdhni kilāsuraḥ
sva-hastaṁ dhātum ārebhe
 so ’bibhyat sva-kṛtāc chivaḥ
Synonyms: 
saḥ — he; tat — his (Lord Śiva’s); vara — the benediction; parīkṣā-artham — in order to test; śambhoḥ — of Lord Śiva; mūrdhni — on the head; kila — indeed; asuraḥ — the demon; sva — his own; hastam — hand; dhātum — to put; ārebhe — he tried; saḥ — he; abibhyat — became afraid; sva — by himself; kṛtāt — because of what had been done; śivaḥ — Lord Śiva.
Translation: 
To test Lord Śambhu’s benediction, the demon then tried to put his hand on the Lord’s head. Thus Śiva was frightened because of what he himself had done.