When this enchantment enters, yell "Surprise!" and put onto the battlefield any number of printed Clown Robot tokens that aren't touching each other, that you hid on the battlefield before you
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) this enchantment, and that weren't spotted by an opponent before you
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) this enchantment.
Robots you control get +1/+0 and have
vigilanceVigilance is a static ability that modifies the rules for the declare attackers step.
Attacking doesn’t cause creatures with vigilance to tap. (See rule 508, “Declare Attackers Step.”)
Multiple instances of vigilance on the same creature are redundant. (CR 702.20).