A retrievable bridge plug includes a housing that includes a slickline connector; a plurality of wheels coupled to the housing, each wheel adjustable from a retracted position within the housing to an extended position from the housing; a motor assembly within the housing and driveably coupled to the plurality of wheels; a seal coupled to the housing; and a controller configured to operate the motor assembly to move the housing through a wellbore on the plurality of wheels in the extended position in response to a particular force on the housing; and activate the seal to seal the wellbore from fluid circulation there through.