If lets say... an Owlbear which has the multiattack trait wants to knock someone down and grapple them. Can the owlbear replace the 2 attack actions covered under the multiattack with a grapple and a shove?
The MM says...
When a monster takes its action, it can choose from the options in the Actions section of its stat block or use one of the actions available to all creatures, such as the Dash or Hide action, as described in the Players Handbook.
So at this point it looks like monsters can indeed replace an attack action with something like a grapple.
A creature that can make multiple attacks on its turn has the Multiattack ability. A creature can't use Multiattack when making an opportunity attack, which must be a single melee attack
This seems to imply that some creatures can make more than one attack action per turn. Its worded similar to the player version...
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn
The snag for me comes up when reading the grapple action text that says..
If you’re able to make multiple attacks with the Attack action, this attack replaces one of them.
The key word being "attack action". Does this mean that since multiattack seems to be a special feature and not the normal "attack action" that monsters may only replace their normal attack action (which they only have 1 of) with a alternate action type instead of replacing both attacks like a PC would be able to? ( Or at least I think PC's can)