Torpor Orb

Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keyword abilities are triggered abilities and will have "when," "whenever," or "at the beginning of" in their reminder text.

Torpor Orb stops a creature's own enters-the-battlefield triggered abilities as well as other triggered abilities that would trigger when a creature enters the battlefield.

The trigger event doesn't have to specify "creatures" entering the battlefield. For example, Captain Storm, Cosmium Raider from the Lost Caverns of Ixalan release has an ability that says "Whenever an artifact enters the battlefield under your control, put a +1/+1 counter on target Pirate you control." If an artifact creature enters the battlefield under your control, that ability won't trigger. If a noncreature artifact enters the battlefield under your control, the ability will trigger.

If Torpor Orb and a creature enter the battlefield at the same time, that creature entering the battlefield won't cause triggered abilities to trigger.