The wither needs three wither skeleton skulls, and on 23 July 2021 prop grinded for them until he had all three. Two dropped “randomly” without a Looting III sword 1.
With the skulls in hand, he and kira decided not to bother with the traditional arena fight. kira’s two-word suggestion was “end portal” 2: summon the wither at an End portal and cheese it. It worked. The server bot soon announced that prop had made the advancement “Withering Heights” 3, and both players earned it.

They crafted a beacon straight away, and “Bring Home the Beacon” 4 and Beaconator followed in short order. The beacon did not sit around as a trophy: it was placed above a hole to speed up the dig for the slime farm at the slime chunk.
See also Wither Slain for the Beacon.
Primary sources
-
i got 2 skulls without looting 3 randomly
-
end portal
-
ProPlayerPlayz has made the advancement [Withering Heights]
-
ProPlayerPlayz has made the advancement [Bring Home the Beacon]

