An old Magic: The Gathering aura spell has seen a 450% price spike. Entangler was worth just $1.30 before the recent Spider-Man set came out, but now it's all the way up to $7.10. It's all thanks to some great synergy with one of the best MTG commanders in the set.
Entangler was released in the 2000 MTG set Prophecy, the final small expansion in Masques, one of the worst block Wizards ever released. Designers responded to their mistakes in the wildly unbalanced 1999 Urza's block with an anemic batch of doo-doo cards, and Prophecy had some of the worst of them, like the Rhystic spells that were essentially useless if your opponent paid a drop of mana. (Except Rhystic Study - I hear that one's pretty good.)
Prophecy did at least also have some experimental card designs, like Entangler, an aura that lets the creature you cast it on block any number of attackers. That's great for the Spider-Man commander Anti-Venom, a creature that can't be dealt damage and converts any damage it would take into +1/+1 counters.
With Anti-Venom enchanted with Entangler, it basically becomes impossible for your opponents to attack you. Or rather, they can do so, but it's counterintuitive and is likely to turn your commander from a decent threat that's hard to deal with to a game-ending wrecking ball that can dish out 21 commander damage in a single turn.
Anti-Venom is one of the most popular commanders from its release, and Entangler is now logged in 2,600 fresh decks on EDHREC. Since this card was only ever printed once, in a set that's now 25 years old, it's safe to assume there are only a limited number of copies available.
This is not the only Magic card that's spiked thanks to Anti-Venom. Phyrexian Vindicator, a creature with a similar damage-blocking ability is moving up in price too, because it plays very nicely alongside everything that works well with Anti-Venom. We've also seen a bunch of smaller price movements for cards like Stuffy Doll.
For more price stories, check out our list of the most expensive MTG cards ever. Or come join the conversation on the Wargamer Discord.