Apple is no longer the only company getting in on the emoji business.

In December, Kim Kardashian launched her own "Kimoji" app that gives users the ability to install Kardashian-related emojis on their phones, while earlier this week Monica Lewinksy teamed up with British company Vodaphone to release a line of anti-bullying emojis. "Emojis are like modern-day cave paintings: simple, direct, visual," Lewinsky wrote in Vanity Fair.

But just because the images are simple doesn't mean that they're easy to use. Inc. rounded up some of the biggest emoji fails, to demonstrate how not to use these images to get your brand's message across:

1. Don't use emojis that imply violence

In April, the Houston Rockets fired their digital communications manager, Chad Shanks, after a tweet went viral for the wrong reasons. The Rockets were about to clinch a win in a playoff game against the Dallas Mavericks, when Shanks sent out a tweet (now deleted) from the Rockets' Twitter account before the end of the game. The tweet said, "Shhhhh. Just close your eyes. It will all be over soon," with a picture of the horse emoji and the gun emoji pointed toward it. The Dallas Mavericks (whose mascot is a horse) replied with a tweet of their own.

Moral of the story: steer clear of the gun icon (and probably the knife emoji while you're at it).

2. Don't use emojis to oversimplify a complex topic

In August, Hillary Clinton caught flack for attempting to collect feedback from voters in an unusual way.

Instead of feeling engaged, many Twitter users were enraged. They felt that Clinton and her team were implying that voters needed to be talked to in a dumbed-down manner on social media. 

Just because millennials use emojis doesn't mean they like communicating exclusively with them (especially on hot-button issues).

3. Don't be tone-deaf

Unfortunately, a lot of brands lack good judgment when using social media, and commentators say more diverse social media teams (i.e., not all white) would help avoid gaffes that come off as racist or insensitive. After Apple released 300 new emojis (including a set of racially diverse faces) in April, Clorox sent out a now-deleted tweet that read "New emojis are alright, but where's the bleach."

But some interpreted Clorox's tweet as wanting to "bleach out" the new emojis.

Clorox quickly issued an apology--and found a better way to use emojis to get its point across.

4. Don't experiment in real time 

In September, ESPN introduced all-emoji recaps of NFL Games. However, it took the company a while to learn how to write emoji recaps that everyone could understand. 

After the Patriots scored a 20-13 victory over the Buffalo Bills on Nov. 25, ESPN's Sports Center account sent out this tweet.

Patriots fans thought that the sports media company was referencing a 2007 scandal. The team was fined $250,000, and lost their first round draft pick, after it was revealed that the Patriots illegally videotaped the New York Jets' defensive coaches during a game.

So Sports Center sent out a longer tweet (with words) to clear up any confusion.