Patrick Marshall also threw pool cues, destroyed water coolers and trashed a recreation room at the facility.
Appearing from custody at Falkirk Sheriff Court on Thursday, the 20-year-old had admitted shouting, swearing, uttering threats of violence and repeatedly throwing pool balls, pool cues and other objects at staff and inmates on October 16, 2018.
Marshall also wrecked a water cooler and other fittings, damaged and upended a pool table, threw a chair, flipped over furniture in an attempt to built a barricade and committed a breach of the peace.
That same day, he assaulted a prison guard by throwing a pool ball and struck another officer with a pool cue.
On December 10, 2018, Marshall again shouted, swore and uttered threats of violence.
He also broke a mop and repeatedly struck it against a pool table, threw pool balls at staff, kicked over a water cooler, launched a vacuum cleaner, damaged fixtures and committed a breach of the peace.
Narrating the initial incident, procurator fiscal depute Becca Reid said: “A prison officer saw the accused break a pool cue over his knee and climb onto the pool table.
“The accused then began throwing pool balls in the direction of the witness and four prison officers.
“The witness informed another something was happening. The witness came out and saw the accused standing on the pool table with a broken pool cue.
“The witness asked the accused to calm down and he refused to do so. The accused then began to throw the pool balls towards people.
“The witness opened a fire door to allow the four prisoners to exit safely. Upon their return they observed the accused to throw pool balls and a broken cue in their direction.
“The accused caused the area to become flooded by kicking a drinking fountain off the wall.
“Officers entered the hall. They moved towards the accused who was throwing pool balls and swinging pool cues in their direction. He continued and one struck the witness on the shoulder.
“As officers got closer, the accused continue to throw balls at them and when they were in front of him, he struck out with the broken pool cue. The witnesses put a shield out and the accused jumped off the table.
“Once off the table, they secured him up against the wall.”
The events in December 2018 unfolded when Marshall became involved in a “verbal altercation” with another.
The fiscal depute continued: “He walked back to the recreation room and was trying to get a pool cue.
“He broke a mop and said to staff, ‘Bring it’.”
The court was told Marshall caused £2076 of damage to the water coolers and is currently serving a sentence of seven years and five months.
His defence solicitor said: “He had a difficult upbringing and spent it in social settings.
“There’s not much progress in his ability to deal with the authorities.”
Sheriff Derek Hamilton said: “If you hadn’t been so young and weren’t serving a lengthy sentence, you’re likely to have faced three years and a further 18 months on the second incident.”
Sheriff Hamilton added 27 months on to Marshall’s sentence.