"Fantasy Factory" star Rob Dyrdek is $50,000 closer to building a dream skate park for kids in L.A. ... thanks to a HUGE donation from one of his co-stars.
Dyrdek has been super-passionate about building skate parks where kids can SAFELY skate whenever they want -- and now his former assistant Chris Pfaff (better known as Drama) is taking another cue from his mentor and helping the cause ... with a $50,000 donation.
In fact, Drama is so serious about the cause, he's also donating a portion of the profits from a new shirt and a new hoodie that his skate clothing company will be selling.
TMZ spoke to a rep for Drama ... who tells us, "[Pfaff] worked as Rob Dyrdek's assistant for multiple years picking up a lot of the skills and knowledge that Rob had for his businesses. Now it's Drama's turn to give back to Rob's foundation by opening his very own safe spot skate spot."
Drama will present the check at a charity event for the Rob Dyrdek Foundation in L.A. this weekend. The exact location of the park has yet to be determined.