It's not often that a single stock can drive an entire exchange-traded fund (ETF). That's the idea behind an ETF; a diverised approach to investing that holds small amounts of many companies in one investment instead of just one company to minimize risk and maximize returns. However, when one stock does move an ETF, it makes a big show.

GameStop (GME  ) ignited both a market and media frenzy last week, taking over headlines on all major news outlets and sending stocks to their worst sell off since October as investors tried to make sense of what was happening. Market participants did have reason for concern, as an unprecedented amount of retail investors rallied behind the heavily shorted stock to cause a massive hedge fund short squeeze through an extraordinary multi-session run.

GameStop shares rose from $18.84 at the start of the year to highs of $483 last week. The stock is still trading up over 1,000% for its year-to-date.

That insane rally in such a short amount of time had an impact on the ETFs holding the stock.

Wedbush ETFMG Video Game Tech ETF (GAMR  ), which holds the stocks in portfolio at equal weight based on their position in the video game industry, saw GameStop become the largest weighted holding this month due to the stock's rapid and massive volume change. Currently, GameStop is holding over 26% of the fund's 93 stock portfolio, when it should be holding about 2%.

Another ETF that was impacted by GameStop's epic run was SPDR S&P Retail ETF (XRT  ), which is a broad, equal-weighted index of stocks within the U.S. retail industry. GameStop's surge has caused the stock to hold over 19% of the 84 stock index, when it usually holds closer to 1%.

GameStop's takeover of GAMR had led to the fund rising over 12% for the week and almost 27% for the year-to-date. Likewise, the stock's overweight position in XRT pushed the fund up nearly 9% for the week and about 29% for its year-to-date.

XRT's run-up has lead to a massive outflow for the fund, with investors pulling nearly $700 million from the ETF last week, leaving the fund with just $164 million in total assets, according to Bloomberg.

For GameStop's position to change in these ETFs, the stock's rally will have to meet its end, with its share decline bringing the stock's weighting back down naturally. Otherwise, both of the funds are scheduled to be rebalanced in March.