Weapon Block
Weapon Block and Weapon Barrier are original Objects created for Mega Man Maker and were included in it's debut 1.0.0 release.
Weapon Blocks are 2x2 solid tiles and Weapon Barriers are 1x2 solid tiles that can be destroyed by whatever Weapon or Utility is assigned to them in the Editor (with the special exceptions of Super Arrow and Items 1 thru 3). If no Weapon or Utility is assigned to a Block/Barrier, then the Block/Barrier in question will be grey meaning it cannot be destroyed (with the special exception of the Nothing Weapon setting and Proto Shield combo). These Blocks/Barriers behave like shielded enemies and can reflect player shots though shield piercing weapons can shoot through them leaving the block intact.
In Mega Man Maker version 1.6.0 Horizontal Weapon Barriers that are 2x1 in the Editor were added to Mega Man Maker.