Steyn, the spearhead of the South African bowling attack, posted a video on his Instagram account showing him and a friend thinking they were coming to the aid of a stricken, harmless Brown House snake on an isolated road in the Kruger National Park.
On closer inspection, the 32-year-old Steyn then realised he was just inches away from a deadly Black Mamba.
"So this poor guy was hit by a car, we stopped to move him out the road thinking it was a brown house snake," Steyn wrote in a message alongside the brief footage.
"This post is not to show how brave we were, it's to show that if you don't know what you dealing with then best you leave it alone! Lesson learnt! #wildouthere #blackmamba."
Steyn, the veteran of 82 Tests and 112 one-day internationals, is currently sitting out the limited overs series against England.