I was testing out my newest map when the Cyber Mutants used Radioactive Pulse and made my spiders draw Large Weapon and Laser Spray - I clicked on Large Weapon, then took the Captain's handicap but after that the mandatory effect was not applied to the Laser Spray - I can attack but I cannot click Laser Spray - it is also not jumping up and down as you can see in this picture: Spoiler: Screenshot Spoiler: Battle Text BlackVoidDeath passed. Grossman releases a pulse of radiation. Potemkin took 5 Radiation damage. Mind Leak triggered discard for The Captain. The Captain discarded Psychic Blast. Mutated Chitin reduced damage to Bitey by 5. Bitey took 0 Radiation damage. Mutated Chitin reduced damage to Burney by 5. Burney took 0 Radiation damage. Grossman took 5 Radiation damage. Grossman took 5 Radiation damage. The Captain discarded Reanimate. Invisible Spiders discarded Mutated Chitin. Invisible Spiders discarded Dodge. Cyber Brute discarded Paralytic Poison. The Captain drew a card. Invisible Spiders drew a card. Invisible Spiders drew a card. Cyber Brute drew a card. Cyber Brute drew a card. Potemkin plays Festering Guts. The Captain drew Radioactive Bite. Bitey is having trouble with that large weapon. Invisible Spiders drew Acrobatic Flip. Edit: After that I get to the end of the round without having to or even able to use Laser Spray - now I can discard it if I want, I wont so that I can find out what happens next. Edit2: Dammit, I dont get to find out what happens because one of the Mutants die in the lava pool.
I think your spiders have both acted this turn (they are greyed out), this would be why they cannot attack, even if it is a mandatory action.