Because it was his birthday!
And that's the strange way Indian cricketers celebrate team-mates's birthdays, by smashing cake on the birthday boy's face.

IMAGE: Ishan Kishan dabs Ajinkya Rahane's face with cake as Mohammed Shami and Shubman Gill try to get a piece of the action. Photograph: PTI Photo
Rahane turned 35 birthday on Tuesday, a day before the highly anticipated World Test Championship final against Australia.

The BCCI shared glimpses of the celebrations on its Twitter account.

IMAGE: Head Coach Rahul Dravid feeds the birthday boy. Photograph: BCCI/Twitter

IMAGE: Another No. 3 in the Indian batting line-up (who filled said gent above's cricket boots) does the honours for Rahane. Photograph: BCCI/Twitter