Spright Vs Infernoid : Yu-Gi-Oh! Locals Feature Match | Live Duel 

Nah imagination is a perma spell that doesn‘t trigger on activation but rather as a ignition effect ( on open gamestate the turnplayer has to activate the eff while imagination is already on field and succefully resolved). So the spright player has a window to activate i:p in response to imagination activation or on its resolve. It will summon S:P which will trigger to banish. All of that happens before the infernoid player is allowed to use the onfield effect to fuse

@@ginomeisteryeah you are correct. i re read it and saw that it doest activate on activation its an ignition eff.

This ^ Basically Imagination is just a continuous spell. And you declare its effect by sending it as a cost to fuse. So Anytime before imagination on-field effect is declared is a window for a potential disruption

Used to be Infernoid's best play! Same reason you can use things like Evenly as cost for Droplet.