Red Kryptonite was the worst plot device that was ever employed on Smallville. It was the first of many variations of the green Kryptonite that made Clark (Tom Welling) weak in the TV series. Over the course of the show’s 10 seasons, Clark and his friends discovered numerous colors of Kryptonite, including blue, red, black, silver, and gold - and each type had a different effect on Clark.

In Smallville season 2, Clark purchased a class ring against his parents’ wishes, and as soon as he put it on, it dramatically changed his personality. Because of the ring, Clark let go of his inhibitions, nonchalantly admitted he was in love with Lana (Kristin Kreuk), and began treating the people around him badly. Later, Pete (Sam Jones III) found out that the class ring was made from red meteor rocks. This discovery led Pete and Jonathan (John Schneider) concoct a plan to get Clark out from under its influence. Though they succeeded in reverting Clark back to his normal self, it wasn’t the last any of them saw of Clark Kent’s dark side on Smallville.

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Red Kryptonite was a plot device that was often used for the wrong reasons - and too consistently. Though the red Kryptonite story felt like a standalone episode, it had a long-term impact on the show’s most important relationship, which is the one that he shared with Lana. Because of it, Clark’s romantic feelings for Lana were now out in the open, and he had a long way to go before his friendship with her was back to normal. She was angry about the way he acted, and of course, Clark had no good explanation for his actions.

The way red Kryptonite seemed to come out of the blue and wreck Clark’s growing bond with Lana was not a one-off incident, which is what it should have been. Later in the season, Clark and Lana were about to start dating when a piece of red Kryptonite was slipped into his pocket. Due to this, Clark was caught by Lana in a comprising situation with Chloe (Allison Mack), and once again had to make considerable efforts to get back on good terms with his main love interest. So while Clark’s secret may have been a major obstacle to him moving forward with Lana, red Kryptonite was arguably an even bigger one in season 2, as it set him back when they would grow closer.

The effects it had on Clark’s romance with Lana were repeated to an even greater extent when Clark willingly put on a red Kryptonite ring in the season 2 finale and didn’t lose it until the end of the season 3 premiere. After seeing much more of Clark’s dark side, Lana was understandably so confused by his personality changes that she was no longer sure who the real Clark was throughout season 3. Smallville season 3 used red Kryptonite to set a new direction for their relationship, and it also gave him new regrets to deal with for the next several episodes.

Smallville took a break from red Kryptonite after that, but it did come back into Clark’s life a few more times. One noteworthy occurrence happened in a season 6 episode, which finally flipped the formula. After being infected with red Kryptonite, Clark kidnapped Lana from her and Lex’s engagement party and was secretly caught using his powers by Lana. This time, instead of deepening the divide between them, it served as the first real step toward Lana finding out the truth. It was perhaps the most interesting examples of how red Kryptonite was used, as it seemed that the earlier uses of it were aimed at causing Clark setbacks with Lana. Though Clark on red Kryptonite could be fun to watch, it was disappointing that Smallville didn’t let their relationship progress (or deteriorate) naturally in the show’s early seasons.

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