When a nasty is summoned by a lich, and its monster type has a zombie counterpart, it will instead be replaced by that zombie counterpart.

If a monster that is capable of summoning nasties has successfully rolled to avert conflict, it will avoid summoning nasties for a little while if conflict remains active (even if it succumbs to conflict itself later on).

Add a message for when create monster/create familiar/summon nasties fails to summon anything (may happen in extinctionist games).

Distinguish between monster spells “summon random monsters” and “summon nasties”, allowing lower level casters to summon at-difficulty non-nasties.

Summon nasties can only summon nasties on squares adjacent to the target creature. If there aren’t any available adjacent spaces, it has no effect.

Spell of summon single nasty: summons only one monster, but the game looks at the target’s current gear and defenses and analyzes exactly what sort of monster would be the best for facing it.

All Riders have intrinsic player-style MR, making them immune to death rays, but summon insects and summon nasties don’t work on the Astral Plane.

Wizard-harassment summon nasties should produce a “Monsters appear from nowhere!” message, and this message should force a –More–.

Summoning spells examine how many summoned monsters are currently on the level, and cap it at some point so the level can’t fill up with more and more summonstormed monsters.

Have different summon nasties lists, based on what monster is doing the summoning. If a demon summons, you get mostly demons; if an undead summons, you get mostly undead. Needs some more lists for lawful summoners like titans or Archons and Quest nemesis spellcasters. The current list is kept for the Wizard of Yendor.