I need to work out a system so I actually do this more often...
The biggest fungus (3) stretches itself to strike at Borgnak, but only succeeding in rustling his hide shirt. While it is doing this, Borgnak's hands begin to sting again. Roll a fortitude save.
Another fungus (1) throws itself at Borgnak, also failing to penetrate his hide shirt.
Nitzpak throws his javelin at fungus (2), but he failed to roll his to-hit. GM rolled it anyway, and it was a 23 (15+8). Damage is 10! (1d6+4, because you forgot Point Blank Shot?) The fungus is now pinned to the ground and entirely immobile, with liquid almost flowing out of the wound. (I'm also not sure how you have a +8 to hit. It looks like it should be a +7.)
Borgnak drops the fungus he was grappling in order to draw his terbutje and scream with terror at the fungi around him. The fungi shudder under the force of his breath, but are otherwise unaffected. Orlan bounds in to bite at fungus (1) (swapped because (2) is already dead), dealing 5 damage. There is a lot of fluid seeping out of the bite marks. Orlan did not enjoy biting the fungus, and you suffer a -2 to handle animal checks for 24 hours. Also, Orlan has to roll a fortitude save.
Herbert screams out while bringing his drums around proper and beating on them. Everyone of the party get's a bonus +1 to attack rolls and +2 to damage rolls!
Gamerlord fails to roll his attack roll, so GM does it anyway. Markus swings his terbutje down, striking fungus (1) squarely (5 + 10), splattering it across the forest floor. GM didn't roll damage, because minimum damage was 13. Yeah.
The big fungus's turn is up next, and it... continues throwing itself at Borgnak. This time it penetrates his hide shirt!... only to be balked at the natural fortitude all Orcs share. Nitzak's up next.