All things Wolverine are simply exploding, and Hulk 181 has officially entered the ridiculous stage. 

This past March, I finally joined The Incredible Hulk #181 club (seriously, there is an actual club). After years of hoping and waiting and negotiations that went nowhere, I finally coughed up $700 for mine. It's low grade and doesn't have the Marvel Value Stamp, but it's mine. Since then, I've had it slabbed and graded by CGC, and it came back a qualified 3.5.

At the time, that $700 was about the average price for a raw copy of Hulk #181. I wasn't aiming to flip this one, so as long as my cost was in line with the fair market value, I was fine. Here we are five months later, and that same qualified green-label 3.5 Hulk #181 is selling for anywhere from $1,000 to $1,500. I'm not complaining about my comic's value being double my investment, but that is crazy. The thing is, there's no ceiling in sight. By the end of the year, a qualified 3.5 could realistically break $2,000.

Since Marvel brought Wolverine back to life in the comics with the Hunt for Wolverine and Disney's acquisition of Fox, granting Marvel Studios the rights to put all the X-Men in the MCU, collectors have been clamoring for all things Wolverine. While the first appearance may be the main attention grabber, his other keys are blowing up as well.

One of my particular favorite Wolverine interpretations is soaring. Over the past 90 days, 1982's limited Wolverine #1 has been rising for virtually all grades. Not only is this the first solo title featuring the original Wolverine, but the Frank Miller cover art is among the most iconic for the character. Last year, a graded 9.8 brought as much as $485, and it's averaged $294 in the last three months.

Although not as popular as the limited series, the 1988 Wolverine #1 - the first of many iterations of the ongoing series - is moving as well. You don't have the eye-popping numbers as the 1982 Wolverine #1, but all the grades of the 1988 issue have experienced a modest increase, particularly the 9.8 grade. Two years ago, you could have bought one of these near-mint copies for around $119. In the past three months, it's averaging $164 and the most recent sale was for $183 just yesterday.

Let's not forget about one of Wolverine's most-famous covers: The Incredible Hulk #340. This is one of the most-replicated covers in the industry, and you can see by Todd McFarlane's masterful pencil work exactly why. Not only is the cover amazing, but the interior art is fantastic, plus it's an intense and brutal fight between two of Marvel's toughest brawlers. Like the other Wolverine keys, this one is feeling a surge in popularity. The 9.8 jumped nearly $100 in fair market value over the past two years; in 2016, it averaged $237 before jumping to $333 in 2017. It's still on the move, and its 90-day average currently stands at $385, and four of the past six sales have been for $400; the other two were for $399 and $390.

Want to know one key that's not gaining value? Death of Wolverine #4. Why would it? The Hunt for Wolverine basically made this story a moot point, which is why I advise against investing much in "death" issues. A year ago, when the news first hit that Wolverine was on his way back, DOW #4 became relatively hot. The standard cover in a 9.8 went from averaging $38 in 2016 to $62 in 2017 with a high of $138. However, the FMV has dropped to $49 dating back to last August, and it's brought no more than $81 since January.