According to him, he saw the bear and took off toward Happy Jack road.

I've ridden Happy Jack 13 years and have never seen or heard of a bear in the area. Today I almost collided into one at the Haunted Forest/Old Happy Jack junction. It was running across the trail. It was NOT a small bear. I slammed on my brakes about 15 feet from it. It saw me, squared up then slowly backed into the timber. I was like "f this noise I'm out" and turned around.

Jon Cicarelli, the mountain biker, said he took off on foot through some wetlands and grasses too tall to ride his bike through.

Although he was thankful he made it out unscathed, he said he was a little bummed he had to bail on the trek because he was pretty close to making some personal best times. But luckily for him, there is a next time.

It is recommended for people to carry bear spray with them in case of any dangerous bear encounters.

Wyoming Game and Fish recommends these precautions if you see a bear:

Try to remain calm, slowly back out of the area, and have a defense ready.
Never run away from the bear.
Do not challenge the bear with any aggressive body language or direct eye contact.
If the bear begins to approach, stand your ground and use bear spray if available.

See more tips here at the National Park Service.

Below is an unrelated of a park ranger using pepper spray to deter bears from a crowd of tourists in Yellowstone.