It's feared by many and avoided completely by few.
It's injury, and it can ruin a dream season.
Injuries are a part of athletics. Some are minor, but others can alter a season in one play.
The Tonganoxie High football team is no different than any other squad.
The Chieftains have endured different levels of injury. Despite some setbacks, Tonganoxie sets at 6-1 on the season with two district games left before what is hoped to be a fourth consecutive playoff berth.
Three current players are dealing with different stages of injury.
Senior Brandon Willis returned this season after a knee injury last fall sidelined him for much of his junior year.
The injury required offseason surgery, but he is back for his senior season.
The injury occurred during Week 3 last season.
Junior Derek Parrett was a few plays into the second game of this season when he fell and injured his collarbone. Parrett battled the injury and returned in Week 6 against Basehor-Linwood.
And then there's Ryan Bennett. The senior was playing against Piper in Week 3 this season when a Piper player fell on the back of his leg. Bennett subsequently broke his foot. Unlike Willis and Parrett, Bennett hasn't had time on his side. He might be able to play during the playoffs -- if the Chieftains advance.
Two years ago, Tonganoxie finished the regular season at 8-1. Some didn't expect the Chieftains to equal that record last fall, but THS did. And in the process, the Chieftains won their first district title in years.
Willis, though, had to watch much of it from the sidelines after tearing the ACL and MCL in his right knee.
"It sucked," Willis said. "Especially since the team was doing so good."
Willis still was part of the team.
"I guess all I did was whatever I could in practice to help," Willis said. "I showed up every day to help.
"I couldn't run, but I tried to keep everybody motivated and on track."
The running back did get one last crack at football his junior year. Willis played against Hayden in Topeka in the second round of the Class 4A playoffs.
"It wasn't right, I could tell it wasn't right," Willis said about his knee. "All I wanted to do was get in for one play.
Willis was on the field for more than one play against Hayden. But after the season, he found out he would need to have surgery.
After rehabbing for six months in the off-season, he was ready to go -- just in time for this fall.
Wearing a brace, Willis was ready to go for this season. The brace protects that knee, but there's still the uncertainty of having a reconstructed joint.
Willis described how he felt walking onto the field for the first time since surgery in the season opener against Lansing.
"I was nervous at the beginning, but once you get your head off of it, you don't pay attention to it anymore," Willis said.
The senior hasn't appeared to miss a step in his last year. Willis has 429 rushing yards through seven games. He is the team's No. 2 rusher behind quarterback Jeff Hughes.
After surgery, Willis became an impromptu meteorologist. As is the case for many with reconstructive surgery, Willis' knee starts to hurt when the weather changes.
"Usually before it gets cold you can tell," Willis said. "It just gets tight."
Willis has done well in his senior year, but he became more cautious after the surgery.
"You can't just go full bore," Willis said. "You do, but every time a guy falls on your leg, you've just got that phobia. Is it all right?"
The injury has caused some "dealable pain." Willis, though, admitted that Tonganoxie's 6-1 record helps take his mind off the injury. He keeps everything in perspective -- brace and all.
"Now I have more equipment to put on," Willis said with a smile.
On the third play of the game against Bishop Ward in Week 2 this season, Parrett, on defense, pursued a sweep play.
Parrett fell to the ground and landed on his head and shoulder.
At halftime, Parrett said the team trainer told him he appeared to have a bruised collarbone.
After getting x-rays, a doctor said he thought Parrett had a broken collarbone. Another doctor said a growth plate had shifted.
Parrett continued to practice, but in a limited capacity. He started wearing a special pad to protect the injured area.
The junior missed a few games before doctors told him something he wanted to hear -- he was cleared to play.
Parrett played against Basehor-Linwood two weeks ago and played against Bonner Springs on Friday.
The injury has healed well in Parrett's mind. He said he as the occasional "tingling pain," but he said it doesn't really hurt that much. He said he's back to running at full speed.
He just hopes no offseason surgery is in his future, as it was for Willis last year.
"I actually was glad it wasn't my senior year," Parrett said. "That way I had another year to play."
Another year of eligibility isn't an option for Bennett.
The senior opened the season as the team's No. 1 center, a position that has taken time for Bennett to achieve.
But just three games into the season, Bennett took an unfortunate tumble.
Jeff Frank was blocking a Piper defender when the Piper lineman fell on the back of Bennett's leg.
X-rays showed Bennett had a cracked bone on the outside of his left foot. Bennett has been in a cast ever since.
On Monday, doctors told Bennett he likely would be in the cast for four more weeks.
That puts the calendar near the second round of playoffs. If Tonganoxie can advance that far, Bennett might be able to return.
"But the doctor said it was healing real well," Bennett said.
The senior's next appointment is in two weeks. He hopes at that time the cast can come off.
"That's what I'm hoping anyway," Bennett said.
Bennett said it was hard to describe what was going through his mind when he hit the ground during the Piper game.
"I was just like 'I can't believe this is happening,' it being my first injury.
"And I knew something bad happened because I've never felt pain like that before."
He found out the next day it was broken.
"I was just devastated, really," Bennett said. "Because I've been doing this for a long time and been waiting for my senior year for a long time. And to end it the way I did, I was shocked."
Parrett said his teammate's injury was unfortunate.
"I think that's a total bummer," Parrett said. "I felt totally bad for him.
"I'd probably be crying if I had to sit out my senior year."
Bennett, though, continues to be a vital part of the team. Almost an additional line coach, Bennett helps the younger players as best he can.
"Whenever I can help them I will," Bennett said. "I'll give them pointers and stuff."
As more games go by, watching his teammates play becomes difficult.
But as more games become history, Bennett gets closer to taking off the cast.
"I'm hoping it will keep healing well and maybe I'll get out there for the playoffs," Bennett said. "That's my goal anyway.
"There's a slim chance I can. I'm going to do everything in my power to get back as soon as possible."