A handful of stocks are enjoying a sort of halo effect from investors' bitcoin mania — but market watchers are cautioning against getting into the names at current levels.

Shares of Overstock.com have surged 118 percent in the last three months as the company announced it would enter into the blockchain and cryptocurrency space.

Meanwhile, the shares of a small biotech company, which only just recently announced it would incorporate blockchain technology into its business, are on a massive tear. The company, formerly known as Bioptix, changed its name to Riot Blockchain in October -- and instantly saw a surge in its share price. The stock has had a meteoric rise, soaring 586 percent in the last three months.

Investors ought to stay away from both names if they do not understand that cryptocurrencies are highly volatile and speculative instruments, said Ari Wald, head of technical analysis at Oppenheimer.

"Between these two related stocks, structurally one could make the case for Overstock over Riot," Wald wrote in an email to CNBC on Monday.

The trend appears higher for Overstock.com, Wald said, and could theoretically rise back to even its all-time high of $77 based upon a technical analysis.

"Ultimately, it could make its way back to that $77 level if you're a long-term investor. From a near-term basis, just given some extended near-term conditions, you might have to go through a little bit of volatility until you get to those higher price levels," Wald said Monday on CNBC's "Trading Nation."

Shares of Riot Blockchain, which have been traded in a highly volatile manner over the last several sessions, are still in a long-term trend of "lower highs," and selling pressure could soon emerge, Wald said.

Overstock.com does not appear attractive in the least to Eddy Elfenbein, portfolio manager at AdvisorShares.

"I would stay away from this ... very far," Elfenbein said Monday on "Trading Nation."

"It's doubled in the last 90 days, and it's still below its high. There are a lot of legitimate debates about bitcoin, but this is an overshoot of that debate," he said, citing the stock's massive recent run.

Ultimately, Elfenbein said, bitcoin is a "legitimate debate ... [but] these are signs of a top."