Paul Rudd and Jason Segel dissected the nature of adult male friendships in 2009’s “I Love You, Man,” and Rudd is back exploring similar terrain in “Friendship,” which plays like a cracked mirror version of the former film.

The igniting agent here is Tim Robinson, the sketch comedy oddball who has made his Netflix series “I Think You Should Leave” an uproariously funny piece of outsider art. Robinson, in his first feature film starring role, brings such an absurd, wild-card presence that he turns “Friendship” into its own demented, extended sketch, stretched to feature length and ramped up for maximum awkwardness.

Robinson plays Craig Waterman, a nerdy desk worker at Universal Digital Innovations, a tech company that implements strategies to make people more addicted to their phones. He’s married and has one teenage son with his wife, Tami (Kate Mara), who recently beat cancer and mentions her ex-boyfriend as frequently as she can.

Craig gets stars in his eyes when he brings a misdelivered package to the door of his neighbor, Austin Carmichael (Paul Rudd), a weatherman at the local TV station. Austin smokes cigarettes, plays in a band and knows sewer routes below the city (they live in generic Clovis, USA), all of which make him seem like the kind of awesome guy that every 12-year-old boy or stunted male adolescent would think is the most radical dude in town. (It helps that Rudd plays him as coolly and casually as he has any character since “Anchorman.”)

At first, Craig and Austin strike up a casual friendship, and the feeling of companionship gives Craig a sense of belonging he hasn’t felt in years. You can see his inner fire burning again. But their friendship is short lived, and when Austin tries to break things off with his new pal after a night gone awry, Craig refuses to let go, and like many a Tim Robinson character before him, he keeps digging the hole deeper and deeper until he can no longer see the surface above him.

“Friendship” is an exaggerated study of modern masculinity and the corroded, festering wound of male loneliness and Robinson is a hilarious time bomb of discomfort. The film identifies small moments of bizarro humor — Craig buys all his clothes from fictional clothing label Ocean View Dining, a psychedelic trip results in a monumentally mundane trip to a popular fast food establishment — that seem to come straight from the “I Think You Should Leave” playbook.