Zac Efron regrets heading out on a camping trip with friends for Memorial Day weekend in May (10) after he suffered a severe allergic reaction to poison oak.
The High School Musical star developed a rash caused by the plant after going cliff jumping with friends during the annual American holiday.
And the 22 year old confesses his reaction was a horrific sight.
He tells Details magazine, "I went backpacking over Memorial Day weekend and I just got the worst poison oak. It was my first time getting it. Dude, it's like everywhere. Everywhere! I can't even begin to show you, because you'll get so grossed out. I look like a zombie from Dawn of the Dead."