Shove is a status effect characterized as inflicting a subtractive percentage speed modifier by letting the tower itself collide onto the bloon. It is introduced in Bloons TD 6 with the introduction of the Heli Pilot's MOAB Shove upgrade. It is part of the damage types family.
Shove is represented on the Bloons Wiki as 
, the upgrade icon for MOAB Shove in Bloons TD 6, as MOAB Shove and its later upgrades are the only upgrades to inflict such a status effect.
Shove is subset of Knockback 
due to that they both Knockback Bloons but Shove is dependent on position of the tower rather than based on projectiles. It is not stackable or based on fixed distance reversal like with the Press 
status effect, but rather non-stackable and percentage-based.
All attacks require an upgrade in order to have the Shove status effect.
