It’s a blood-sucking fight for online Halloween sales, where Amazon is digging the grave for niche Halloween retailers.

Consumers buy Halloween goods from mass merchant giants, like Amazon.com Inc., No. 1 in the Internet Retailer 2017 Top 500, Wal-Mart Stores Inc. (No. 3), eBay Inc. and Target Corp. (No. 20), and from small niche sites such as Spirit Halloween, Halloween Express, Halloween Costumes Wholesale and Halloween City.

For 2017, the National Retail Federation projected that consumers would spend $9.1 billion online and offline on Halloween goods, which include costumes, candy and decor, up from $8.4 billion in 2016. In NRF’s annual Halloween survey of more than 7,000 shoppers, 22% said they would buy Halloween goods online.

Online sales of Halloween costumes increased 29% in October compared with a year ago, according to Slice Intelligence, which analyzes online sales based on the email receipts of a panel of 5 million consumers. Slice declines to reveal dollar figures.

An analysis of the Halloween season finds that Amazon is grabbing a large share of online Halloween sales. The web giant sold $52 million worth of costumes this season and $19.5 million in candy, according to retail analytics firm One Click Retail. Amazon’s traffic and Halloween conversions peaked closer to Oct. 31, while smaller retailers experienced peaks earlier in the season. Many shoppers may have flocked to Amazon for its free two-days-or-less shipping guarantee available to Prime loyalty members; many smaller Halloween retailers don’t offer this service.

Here is a look at online Halloween shopping this season and how Amazon affects the season.

Traffic to niche Halloween retailers, such as SpiritHalloween.com and HalloweenCostumes.com, slows after Oct. 24, while Amazon’s traffic spikes around this time.

Amazon’s costume purchasers as a percent of total site visitors follows this pattern, as it increases as Halloween approaches.

In terms of overall traffic in October, Amazon is one of the few retailers that grew its web traffic year over year in October 2017 compared with October 2016, according to web measurement firm SimilarWeb. In fact, most of the smaller online retailers had year-over-year web traffic declines.

Brad Butler, chief operating officer at HalloweenExpress.com, disputes the exact figures from SimilarWeb, and says traffic to his site declined 11% in October compared with 2016. Sales and profits were up, however.

“We attribute the lower traffic to the fact that we had fewer retail stores,” Butler says. “The retail stores generate a lot of traffic in terms of using the locator and general product research.”

Online sales for Halloween decor from retailers such as Michael’s, Grandin Road (part of HSN Inc., No. 28) and Jo-Ann Fabrics (No. 308) happened earlier in the Halloween season, and peak the week of Sept. 11-17 (Monday-Sunday), according to marketing analytics firm Jumpshot, which is based on its review of more than 160 billion monthly clicks made by 100 million consumers.

Costume conversion rates, however, peak later in the season around the two-week period of Oct. 9-22.

In terms of marketing, Amazon increased the volume of its Halloween email marketing campaigns as the season went by, sending only six Halloween emails Oct. 1-11 compared with 46 campaigns Oct. 12-31, according to email marketing vendor eDataSource.

Similarly, Amazon.com generated more paid search clicks as the season progressed, according to an analysis of 823 Halloween-related keywords by search marketing data provider Adgooroo. Amazon accounted for 26.4% of the text ad clicks Oct. 25-31, which was an increase from 12.0% during Oct. 16-24 and 13.6% in the weeks of Sept. 1-Oct. 15.

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