Regulusmon

[On Play] [When Digivolving] By trashing 1 card with [Gammamon] in its text from your hand, give 1 of your opponent's Digimon ＜Collision＞ (During this Digimon's attack, all of your opponent's Digimon gain ＜Blocker＞, and must block if possible.) and "[Start of Your Main Phase] This Digimon attacks." until their turn ends. [On Deletion] You may play 1 [Canoweissmon] or 1 level 4 or lower Digimon card with [Gammamon] in its text from your trash without paying the cost.

Inherited effect

[On Deletion] You may play 1 level 4 or lower Digimon card with [Gammamon] in its text from your trash without paying the cost.

Alternate effect

[Digivolve] Lv.4 w/[Gammamon] in text: Cost 3