Each room as you journey through Undercity has nice effects for various Commander battlefield states, and the final room is going to be awesome for most Commander decks that play a reasonable number of creatures
Second Ability: At the beginning of your upkeep, if there are four or more land cards in your graveyard, and you both own and control Titania, Voice of Gaea and a land named Argoth, Sanctum of Nature, exile them, then meld them into Titania, Gaea Incarnate Titanias very easy to get into play and is interesting in that she wants your lands in the graveyard
Shadowspear If Basilisk Collar is the efficient assassin, Shadowspear is the polished executioner
But because it can also Proliferate, its versatility skyrockets
It's a highly versatile effect, so it's a shame that it's so restrictive, but I think it's going to be a somewhat strong peculiarity
Even without Lickitung in the picture, its common for games to be decided with only a few cards left in deck for both players, or most commonly, for you to need resources and be stuck with a dead Professor Oak