What does “gemobbt” mean in German?

This story about a bullied boy uses gemobbt, the past participle of mobben — a verb Germans built directly from English “to mob.” Once borrowed, it was fully naturalized: mobben conjugates like any regular German weak verb, with the standard ge-…-t participle pattern, exactly as if it had always been German.

German absorbs English verbs this way all the time — see also chillen (to chill, → gechillt), downloaden (→ gedownloadet/downgeloadet), and updaten (→ upgedatet). The loanword supplies the meaning; German grammar supplies the conjugation, no exceptions made.