Sun City - Former world number one Luke Donald had to dodge a charging baboon before grabbing the lead at the Nedbank Challenge in South Africa on Friday.
The Englishman missed the course record by one shot after sinking nine birdies to open up a two-shot advantage at Sun City's Gary Player Country Club, but is likely to remember his round for an unwanted visitor on the 13th.
As he prepared to hit an iron, a baboon stormed the fairway and headed directly for him.
Donald moved away from the ball and allowed the animal to pass safely before composing himself to hit a good shot onto the green and sinking his putt for birdie.
Donald had birdied six of the first nine holes as he went out in 30.
He added three more on the back nine before missing a chance at the last to equal compatriot Lee Westwood's course record of 62, set in 2011.
Donald, seeking his first European Tour win since the BMW PGA Championship in 2012, is 10 under par and leads by two from overnight leader Ross Fisher, who hit 70 in his second round.
"It was a fun day, every time you have one of those rounds where you feel at ease and calm and are hitting the shots you are trying to hit, it's great," Donald told reporters.
"After being chased by a baboon on 13 I managed to hit a good shot into the green and make a birdie there, so I was very happy."
Frenchman Alexander Levy followed up his opening round 68 with a steady two-under-par 70 to lie in third at six under and still in the hunt for the $1.25 million first prize.
Former world number one Westwood carded a two-under-par 70 on Friday and is on the same score for the championship.
Defending champion Thomas Bjorn of Denmark followed his woeful eight-over 80 in the first round with a steady par 72, while world number 13 Martin Kaymer, the highest-ranked player in the 30-strong field, could only manage a 75 in his second round and is at five over par.
Welsh Ryder Cup player Jamie Donaldson, who finished second at Sun City last year, withdrew from the tournament before the second round after suffering a severe migraine and dizziness on Friday morning. He had shot 74 in his first round.
Second round scores in the Nedbank Golf Challenge at the Gary Player Country Club, Sun City, South Africa on Friday (GBR/IRL unless stated; par 72):
134 - Luke Donald 71 63
136 - Ross Fisher 66 70
138 - Alexander Levy (FRA) 68 70
139 - Danny Willett 71 68
140 - Marcel Siem (GER) 68 72
141 - Charl Schwartzel (RSA) 70 71, Brendon Todd (USA) 73 68, Tommy Fleetwood 74 67, Tim Clark (RSA) 70 71, Thongchai Jaidee (THA) 71 70
142 - George Coetzee (RSA) 68 74, Lee Westwood 72 70
143 - Stephen Gallacher 70 73, Louis Oosthuizen (RSA) 70 73
144 - Brooks Koepka (USA) 70 74, Miguel Angel Jimenez (ESP) 70 74, Shane Lowry 72 72, Jonas Blixt (SWE) 71 73, Pablo Larrazabal (ESP) 73 71
145 - Kiradech Aphibarnrat (THA) 72 73, Dawie Van Der Walt (RSA) 73 72
146 - Joost Luiten (NED) 72 74
148 - Marc Warren 75 73
149 - Jaco Ahlers (RSA) 74 75, Martin Kaymer (GER) 74 75
150 - Kevin Na (USA) 77 73
152 - Thomas Bjorn (DEN) 80 72
154 - Mikko Ilonen (FIN) 76 78
155 - Danie Van Tonder (RSA) 77 78