Definition
To sneak up to (someone or something) with the intention of causing harm.
Origins
From roll up + on; semantically and morphologically parallel with roll up + to.
How People Actually Use It
verb. To arrive unannounced with the intention of delivering a beat down or to otherwise fuck someone up, esp. for retaliation of prior slight. Synonymous with "Ride on"
"Chris:"T shorted me 14 grams on my last buy." Clint: "That bastard. Gonna have to roll up on him""
Source: Urban Dictionary