Is this familiar? An undrafted point guard signs with the Golden State Warriors, spending ample time in the developmental league until injuries to his NBA team give him an opportunity to shine. He starts putting up career-best scoring numbers and helping teams to victories, electrifying crowds with his confidence and proving he belongs in a league that doubts him, just because of where he came from.

That describes “Linsanity,” the breakthrough month that Jeremy Lin enjoyed with the New York Knicks in February 2012. But it also describes the hot run of play by Pat Spencer, who has seized an opportunity with Steph Curry out. He’s averaged 16 points, 5.8 assists, and a steal per game in four December games while shooting 65% from the field and making 75% of his three-pointers. Like Lin, many people don’t believe in Spencer, just because of the way he looks — cop mustache, t-shirt under his jersey — and his background, an elite college lacrosse career.

Lin was the first American-born player of Taiwanese or Chinese descent to play in the NBA. Spencer is the first winner of the Tewaaraton Award, the Heisman Trophy of lacrosse, to play in the NBA. Both resoundingly answered their doubters.

Call it Laxsanity. Spencer is playing winning basketball, limiting turnovers and hitting tough shots. He’s also playing with vocal confidence that belies his lack of basketball experience — he played only one college season — and shows that lacrosse may have a level of trash talking many of us never realized.

Granted, Lin is a devout Christian, so he might have chosen more family-friendly language when he shouted at an opposing crowd. But Spencer comes from the mean streets of Davidsonville, Maryland, and they don’t play around in Anne Arundel County.

What’s sparking Spencer’s surge? Some of it is simply opportunity. The Warriors are missing Steph Curry, while new signees De’Anthony Melton and Seth Curry are still working their way into shape. With Brandin Podziemski struggling with turnovers and Moses Moody annoying Kerr, Spencer is grabbing his chance and making himself indispensable. He’s shooting 44.4% on three-pointers this season on greatly increased volume. Spencer has already doubled his career three-point totals this year in 17 games.

To be clear, Spencer is not a lacrosse player who happens to play basketball. He is a basketball player who got a lacrosse scholarship instead, because he has preternatural passing ability and was only 5-foot-4 as a high school freshman. So he played lacrosse for four years, setting the college record for assists and making four All-American teams, then casually decided to play a year at Northwestern and become a professional basketball player.

We haven’t seen a Linsanity-esque cultural groundswell behind Spencer yet, but it could come. Imagine when fans start wearing midriff-bearing lacrosse pennies to the Chase Center to support Laxsanity, proudly rocking baggy shorts in the wintertime and displaying a healthy amount of lettuce from the back of their Warriors caps. Or even a t-shirt with Spencer’s screaming face from Philly captioned, “RE-LAX.”

Will Spencer continue in the rotation when Curry returns? Even with two Curry brothers on board, it really seems like he will. But the Warriors need to learn from the cautionary tale of Jeremy Lin’s time on their own team. After he played 29 games as a rookie, the Warriors released Lin and his highly affordable contract in order to give an offer sheet to DeAndre Jordan, one that no one outside the Warriors front office expected to actually work.

Spencer is in a similar roster crunch. He’s on a two-way deal, which means he can play only 50 games and isn’t eligible for the playoffs. The Warriors have a full 15-man roster after signing Seth Curry, and are right up against the luxury tax apron. There’s no urgency yet — Spencer has 33 games left before hitting his limit — but at the deadline, the team may well aim for two-for-one or three-for-two trades so they can keep Laxsanity going all season.